Theming not working in V14 same as V12?

Years ago (Nextcloud 11 I think) I made a modification to the files app to include another option in the ‘+’ menu. Instead of modifying core, I made a copy of nextcloud/apps/files/js/filelist.js into nextcloud/themes/apps/files/js/ and made my changes in the themes directory.

Recently upgraded a test instance to v14 and these javascript changes in the themes/ directory do not seem to be picked up now. Has something changed with v14 in regards to the modified javascript?