LiquidThreads has this little problem that you could fix:

MWDeprecationWarning: Use of "mwEditButtons" property is deprecated. Use mw.toolbar instead

We are getting the warning above from this file:
https://bits.wikimedia.org/static-1.23wmf3/extensions/LiquidThreads/lqt.js
when I click on any "Reply" buttons (with the classic edit toolbar enabled).

That line should just be removed, mwEditButtons is no longer supported.

See

Bug 56935 - MWDeprecationWarning: Use of "mwEditButtons" property is deprecated. Use mw.toolbar insteadtranslation

Please ask any questions in the bug report. You will have better chances for quicker and better answers from the project maintainers and other community contributors.

Students are required to read Wikimedia's general instructions first. Patches should be submitted to Gerrit and reference the bug report in the commit message. Improvements to an initial patch must be submitted as an amendment  to the initial patch, not as new patches.