F-Droid json parsing test. Below is index-v1.json structure from f-droid. I tried to parse this json using Python (attached below)

debug.json

{
  "apps": [
    {
      "authorName": "Lo\u00efc Teyssier",
      "categories": [
        "Science & Education"
      ],
      "suggestedVersionName": "1.3.1",
      "suggestedVersionCode": "14",
      "issueTracker": "https://github.com/lolo-io/OneList/issues",
      "license": "MIT",
      "sourceCode": "https://github.com/lolo-io/OneList",
      "added": 1568851200000,
      "icon": "com.lolo.io.onelist.14.png",
      "packageName": "com.lolo.io.onelist",
      "lastUpdated": 1604016000000,
      "localized": {
        "en-US": {
          "description": "1List is a simple app to manage several lists from only one screen.\nAdd items to a list with only one click. Browse, view, organize your lists from only one screen.\n\nFeatures :\n\t- User friendly lists management and smooth navigation\n\t- Add, delete, edit items in your lists\n\t- Move items within your lists\n\t- Mark items as done or undone\n\t- Add comments on each items\n\t- Create an unlimited number of lists\n\t- Move, edit, remove your lists\n\t... more to come in the near future\n",
          "featureGraphic": "featureGraphic_-zO6p3BS0xLAuhxcwHFYOTtFYcg9BEQsyiTN2ILvavs=.png",
          "name": "1List - Simple Lists for TODO, Shopping, Movies...",
          "phoneScreenshots": [
            "screen1.png",
            "screen2.png",
            "screen3.png",
            "screen4.png",
            "screen5.png",
            "screen6.png"
          ],
          "summary": "Simple app to manage several lists from only one screen"
        },
        "fr-FR": {
          "featureGraphic": "featureGraphic_-zO6p3BS0xLAuhxcwHFYOTtFYcg9BEQsyiTN2ILvavs=.png"
        }
      }
    },
    {
      "categories": [
        "Games"
      ],
      "changelog": "https://github.com/mattvchandler/2050/releases",
      "suggestedVersionName": "1.0.10",
      "suggestedVersionCode": "190010010",
      "issueTracker": "https://github.com/mattvchandler/2050/issues",
      "license": "MIT",
      "sourceCode": "https://github.com/mattvchandler/2050",
      "added": 1558051200000,
      "packageName": "org.mattvchandler.a2050",
      "lastUpdated": 1693608133000,
      "localized": {
        "en-US": {
          "description": "Much like the original, you start with small numbered pieces and combine\nlike-numbered pieces into progressively larger ones, working toward 2048.\n\nUnlike the original, the pieces are free to move in any direction, bounce off of\nthe walls and each other, are subject to gravity, and grow progressively larger.\n",
          "featureGraphic": "featureGraphic_Nj1yhypMv3b68y_bv7xacNkeyv23BMkgH2mb3xy-hGU=.png",
          "icon": "icon_3BMQD76YZDYHbtVP8WR8CTKi6E7pd6L82YveKdLHjR4=.png",
          "name": "2050",
          "phoneScreenshots": [
            "scrn_phone_land_1.png",
            "scrn_phone_land_2.png",
            "scrn_phone_land_3.png",
            "scrn_phone_port_1.png",
            "scrn_phone_port_2.png",
            "scrn_phone_settings.png"
          ],
          "sevenInchScreenshots": [
            "scrn_tablet_7_land.png",
            "scrn_tablet_7_port.png"
          ],
          "summary": "A game loosely based on 2048, but with circles instead of squares",
          "tenInchScreenshots": [
            "scrn_tablet_10_land.png",
            "scrn_tablet_10_port.png"
          ]
        },
        "id": {
          "description": "Sama seperti yang asli, Anda mulai dengan potongan angka kecil dan gabung potongan yang sama angka sehingga menjadi potongan yang lebih besar ke angka 2048.\n\nBerbeda dengan yang asli, potongannya bebas bergerak ke arah mana pun, mantul di dinding dan satu sama lain, tunduk pada gravitasi, dan tumbuh membesar.\n",
          "summary": "Sebuah permainan yang didasarkan pada 2048, tapi menggunakan lingkaran, bukan ko"
        }
      }
    }
  ],
  "packages": {
    "com.lolo.io.onelist": [
      {
        "added": 1604016000000,
        "apkName": "com.lolo.io.onelist_14.apk",
        "hash": "31b226b7d595f31a636a9ee3772bde3e502517ac8855c56a4258d140648b2df2",
        "hashType": "sha256",
        "minSdkVersion": 16,
        "packageName": "com.lolo.io.onelist",
        "sig": "88d4c71efea79488eb63d432950ca342",
        "signer": "f4f7234076e3f87babf78d0b3a2321f985958212151a528390284e3e5a9262dd",
        "size": 2539126,
        "srcname": "com.lolo.io.onelist_14_src.tar.gz",
        "targetSdkVersion": 29,
        "uses-permission": [
          [
            "android.permission.WRITE_EXTERNAL_STORAGE",
            null
          ],
          [
            "android.permission.READ_EXTERNAL_STORAGE",
            null
          ]
        ],
        "versionCode": 14,
        "versionName": "1.3.1"
      },
      {
        "added": 1577664000000,
        "apkName": "com.lolo.io.onelist_12.apk",
        "hash": "8e1a324244b8f3184e1da0f33d9a6fb7112d01414837ba7d470746938e15e076",
        "hashType": "sha256",
        "minSdkVersion": 16,
        "packageName": "com.lolo.io.onelist",
        "sig": "88d4c71efea79488eb63d432950ca342",
        "signer": "f4f7234076e3f87babf78d0b3a2321f985958212151a528390284e3e5a9262dd",
        "size": 2434324,
        "srcname": "com.lolo.io.onelist_12_src.tar.gz",
        "targetSdkVersion": 28,
        "uses-permission": [
          [
            "android.permission.WRITE_EXTERNAL_STORAGE",
            null
          ],
          [
            "android.permission.READ_EXTERNAL_STORAGE",
            null
          ]
        ],
        "versionCode": 12,
        "versionName": "1.2.3"
      },
      {
        "added": 1577059200000,
        "apkName": "com.lolo.io.onelist_11.apk",
        "hash": "6412a2b1c1629c0936505a0654440c266cc822be6d40f1a89d9b723b306a9452",
        "hashType": "sha256",
        "minSdkVersion": 16,
        "packageName": "com.lolo.io.onelist",
        "sig": "88d4c71efea79488eb63d432950ca342",
        "signer": "f4f7234076e3f87babf78d0b3a2321f985958212151a528390284e3e5a9262dd",
        "size": 2434383,
        "srcname": "com.lolo.io.onelist_11_src.tar.gz",
        "targetSdkVersion": 28,
        "uses-permission": [
          [
            "android.permission.WRITE_EXTERNAL_STORAGE",
            null
          ],
          [
            "android.permission.READ_EXTERNAL_STORAGE",
            null
          ]
        ],
        "versionCode": 11,
        "versionName": "1.2.2"
      }
    ],
    "org.mattvchandler.a2050": [
      {
        "added": 1693608133000,
        "apkName": "org.mattvchandler.a2050_190010010.apk",
        "hash": "98a0e75e589c319093db56cf98bfa32d920b9436a9cbe7c30b32dcf7a4a6d284",
        "hashType": "sha256",
        "minSdkVersion": 19,
        "nativecode": [
          "arm64-v8a",
          "armeabi-v7a",
          "x86",
          "x86_64"
        ],
        "packageName": "org.mattvchandler.a2050",
        "sig": "2805fa546d280abddb9875ff323b3565",
        "signer": "b5b82827a3823eff1e86b683977d4a61171941d7a2a9c8632839ad8a45f28759",
        "size": 5079962,
        "srcname": "org.mattvchandler.a2050_190010010_src.tar.gz",
        "targetSdkVersion": 33,
        "uses-permission": [
          [
            "android.permission.ACCESS_FINE_LOCATION",
            null
          ],
          [
            "android.permission.ACCESS_COARSE_LOCATION",
            null
          ],
          [
            "org.mattvchandler.a2050.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION",
            null
          ]
        ],
        "versionCode": 190010010,
        "versionName": "1.0.10"
      },
      {
        "added": 1645833600000,
        "apkName": "org.mattvchandler.a2050_190010009.apk",
        "hash": "9ad9c487017ee06a8f0d5507f775cd19892844e7201e4948a517b90c758a5fbc",
        "hashType": "sha256",
        "minSdkVersion": 19,
        "nativecode": [
          "arm64-v8a",
          "armeabi-v7a",
          "x86",
          "x86_64"
        ],
        "packageName": "org.mattvchandler.a2050",
        "sig": "2805fa546d280abddb9875ff323b3565",
        "signer": "b5b82827a3823eff1e86b683977d4a61171941d7a2a9c8632839ad8a45f28759",
        "size": 4922071,
        "srcname": "org.mattvchandler.a2050_190010009_src.tar.gz",
        "targetSdkVersion": 32,
        "uses-permission": [
          [
            "android.permission.ACCESS_FINE_LOCATION",
            null
          ],
          [
            "android.permission.ACCESS_COARSE_LOCATION",
            null
          ]
        ],
        "versionCode": 190010009,
        "versionName": "1.0.9"
      },
      {
        "added": 1604793600000,
        "apkName": "org.mattvchandler.a2050_190010008.apk",
        "hash": "4c0dc682010b5ec419e12fc50c14887edfeec6fea4c8cbc4ca0641386e1970b1",
        "hashType": "sha256",
        "minSdkVersion": 19,
        "nativecode": [
          "arm64-v8a",
          "armeabi-v7a",
          "x86",
          "x86_64"
        ],
        "packageName": "org.mattvchandler.a2050",
        "sig": "2805fa546d280abddb9875ff323b3565",
        "signer": "b5b82827a3823eff1e86b683977d4a61171941d7a2a9c8632839ad8a45f28759",
        "size": 4396556,
        "srcname": "org.mattvchandler.a2050_190010008_src.tar.gz",
        "targetSdkVersion": 30,
        "uses-permission": [
          [
            "android.permission.ACCESS_FINE_LOCATION",
            null
          ]
        ],
        "versionCode": 190010008,
        "versionName": "1.0.8"
      }
    ]
  }
}

fdroid.py

import argparse, os, sys, json


data = None

app_data = {}


def print_pkg(pkg):
    print(f'Name\t\t: {pkg["name"]}')
    print(f'Summary\t\t: {pkg["summary"]}')
    print(f'Category\t: {pkg["category"]}')
    print(f'min SDK\t\t: {pkg["minSdkVersion"]}')


def fill_keys(app):
    name = summary = None
    minSdkVersion = 999
    if 'name' in app:
        name = app['name']
    if 'localized' in app:
        langs = [ 'en-US', 'en_US', 'en-GB', 'en' ]
        for item in app['localized']:
            if item in langs:
                if 'name' in app['localized'][item]:
                    name = app['localized'][item]['name']
                if 'summary' in app['localized'][item]:
                    summary = app['localized'][item]['summary']
                if name and summary:
                    break
    category = ', '.join(map(str, app['categories']))

    pkg = app['packageName']

    if pkg in data['packages']:
        apk_data = data['packages'][pkg][0]

        if 'minSdkVersion' in apk_data:
            minSdkVersion = apk_data['minSdkVersion']

        app_data[pkg] = {
            'name': name,
            'category': category,
            'summary': summary,
            'minSdkVersion': minSdkVersion
        }


def filter_by_minsdk(apilevel):
    minSdkVersion = 999
    for app in data['apps']:
        pkg = app['packageName']
        if 'minSdkVersion' in data['packages'][pkg][0]:
            minSdkVersion = data['packages'][pkg][0]['minSdkVersion']
        if minSdkVersion <= apilevel:
            fill_keys(app)


# write json with all the app specific data
# follow index-v1.json format
def debug(app):
    jsonf = 'debug.json'

    if os.path.exists(jsonf):
        # since file exists, append data to it
        # if data is not already present
        with open(jsonf, 'r') as file:
            result_json = json.load(file)
        index = -1
        for app_item in result_json['apps']:
            if app_item['packageName'] == app['packageName']:
                index = result_json['apps'].index(app)
        if index != -1:
            result_json['apps'][index] = app
        else:
            result_json['apps'].append(app)
        result_json['packages'][app['packageName']] = data['packages'][app['packageName']]
    else:
        result_json = {}

        result_json['apps'] = [
            app # object
        ]
        result_json['packages'] = {
            app['packageName']: data['packages'][app['packageName']] # array
        }

    with open(jsonf, 'w') as outfile:
        outfile.write(json.dumps(result_json, indent = 2))


def parse_pkg(pkg):
    for app in data['apps']:
        if pkg:
            if app['packageName'] == pkg:
                fill_keys(app)
                print_pkg(app_data[pkg])
                #debug(app)
                break
        else:
            fill_keys(app)


def write_to_file(outf):
    result_json = json.dumps(app_data, indent = 2)
    with open(outf, 'w') as outfile:
        outfile.write(result_json)


def main(inf, outf, pkg, apilevel):
    global data
    with open(inf, 'r') as file:
        data = json.load(file)

    if apilevel:
        filter_by_minsdk(int(apilevel))
    else:
        parse_pkg(pkg)

    if outf:
        write_to_file(outf)


if __name__ == '__main__':
    if not sys.version_info >= (3, 7):
        abort('Requires Python 3.7+')
    parser = argparse.ArgumentParser()
    parser.add_argument('--outfile', help='output json file path')
    parser.add_argument('--apilevel', help='list apps with minimum SDK version less than apilevel')
    parser.add_argument('--pkg', help='An optional pkg name')
    parser.add_argument('infile', help='input index-v1.json')
    args = parser.parse_args()
    main(args.infile, args.outfile, args.pkg, args.apilevel)

python3 fdroid.py index-v1.json --pkg com.lolo.io.onelist
python3 fdroid.py index-v1.json --pkg org.mattvchandler.a2050