OK,
Roughly, all the js versions used in Basel date from when you did the theme, ie cc 2016.
Among them, the moment.js is reported to have vulnerabilities (snyk). Added to all complaints about it, incl. from Google
What authors write now:
we would like to discourage Moment from being used in new projects going forward. Instead, we would like to recommend alternatives that are excellent choices for use in modern applications today.

This, in addition to the former issues / threats mentioned above
Really, this is about security and performance.
Take care
Kind regards