Opera 132 breaks Bookmarks by the Side 2.1.5.

Root cause:
popup.html uses unclosed <command> tags.

Opera 132 no longer parses them correctly, causing several command elements to disappear from the DOM.

neat.js then crashes on:

if (el.tagName == 'COMMAND')

because el is null.

Fix:

popup.html; Close all <command> tags explicitly.
neat.js: Add a null check before accessing el.tagName.

Tested successfully on Opera 132.0.5905.11.

In the meanwhile, users can create un unpacked local version of the extension, correcting the 2 files as above and deleteing the "key:..." line in the manifest.json.