Isn't this file supposed be generated from the script in the build folder and not edited directly?

Not obvious. It could indeed be via helpTOC.php

Therefore, it would depend on the wiki help version which does not exist for 4.0, this could be the reason why weblinks is still proposed.

@mbabker @wilsonge
If this is the case, I guess I can close this.

Yes this file should be generated from the script :)

Hmm. I patched and then ran npm install and the file is NOT modified.
Therefore it seems that it does not depend on anything in build, as far as I could see.

so, which script is it?

helpTOC.php in the build folder

Read:
#22474 (comment)

why would that have anything to do with npm install

its is a standalone php script. it is how the helptoc has been built for a very long time ;)

Therefore, as it can't be run, and I see no solution else for this issue, I am closing it.

of course it can be run

If I run it then toc.son is empty. Therefore I guess #22474 (comment) was correct.
No use for this PR.