A small Anki add-on that enables indentation with the Tab key and outdentation with Shift+Tab in the editor.

__init__.py

from aqt import gui_hooks, mw
from aqt.editor import Editor
from aqt.webview import WebContent


def on_webview_will_set_content(web_content: WebContent, context: object) -> None:
    if isinstance(context, Editor):
        web_content.js.append(f"/_addons/{__name__.split('.')[0]}/indent_with_tab.js")


assert mw
mw.addonManager.setWebExports(__name__, r".+\.js")
gui_hooks.webview_will_set_content.append(on_webview_will_set_content)

indent_with_tab.ankiaddon

indent_with_tab.js

document.addEventListener("keydown", (event) => {
    if (!event.target?.closest(".editor-field")) {
        return;
    }

    if (event.key === "Tab") {
        if (event.ctrlKey) {
            return;
        }

        event.preventDefault();

        if (event.shiftKey) {
            document.execCommand("outdent");
        } else {
            document.execCommand("indent");
        }
    }
});

manifest.json

{
    "name": "Indent with Tab",
    "package": "indent_with_tab"
}