This is a super simple snippet that I paste into my browser console to clear github notifications. Once It has been run once I just push up-enter-up-enter until they are all gone!

clear-github-notifications.js

let foundStuff = false;
let items = document.querySelectorAll('li.notifications-list-item')

items.forEach((item) => {
  if(item.querySelector('img.avatar-user[alt="@dependabot-preview[bot]"]') || item.querySelector('img.avatar-user[alt="@dependabot[bot]"]') || item.querySelector('img.avatar-user[alt="@renovate[bot]"]')) { 
    console.log('did find one');
    foundStuff = true;
    item.querySelector('input[type="checkbox"]').click();
  } 
});

if(foundStuff) {
    foundStuff = false;
    console.log('found some stuff - refresh');
    document.querySelector('button[Title="Done"]').click();
    setTimeout(() => window.location.reload(), 200);
} else {
    console.log('found nothing, next page');
    setTimeout(() => {
      document.querySelector('a[aria-label="Next"]').click();
    }, 200);
}