Removing all comments from a latex file automatically (e.g. before submitting to arXiv). Sang-il has a useful blog post about this here in Korean. Here is an (AI translated) quote from his post:
To delete comments, it is convenient to use the perl command on the arXiv homepage. On Mac, open the terminal and enter the command below.
Perl -pe's/(^|[^\\])%.*/\1%/' < main.tex > main-arxiv.texAfter that, when uploading to arXiv, you can upload the newly created file main-arxiv.tex.
For your reference, there is also an annotation deletion tool arxiv_latex_cleaner made of python.”