They are regular text files. Completely legit. These are javascript text files are used for certain functions of the forum software

ubb_js/assets/jquery.lightbox-plus-rotate.min.js
this allows the post image attachments to be rotated in UBB.threads 7.6 to 7.7.4. It was replaced in 7.7.5 by an entirely new image gallery package.

libs/image.js
this is what processes images when users attach them to posts. it has been in all of the ubb.threads versions for over a decade.

ubb_js/quickquote.js
this allows users to easily quote post content in their replies just by clicking on the "quote" button. it has been in all of the ubb.threads versions for over a decade.

Your antivirus software is reporting false positives.
What Is a False Positive? Sometimes, an overly strict antivirus may flag a file as malicious and report it. This is a case of a false positive, or the erroneous identification of legitimate software as malicious or infected.
https://www.hellotech.com/blog/false-positive