All Factorio mods are just zip files with code and assets inside. So unless the code is obfuscated, the source code is right in the mod file, which is also stored on the mod portal. The statement "If Bob ever stops playing Factorio the mod will be gone" is false. You might have meant to say something about its license, but if I remember correctly, it is quite permissive.

Also, I recommend uploading the mod source code to github or a similar service.

If you rea the license you will see that bob https://forums.factorio.com/viewtopic.php?f=51&t=28573
you ca notice that you can not redistribute the mod if you changed anything about it.

Bob know that you can see the source code but that does not mean that he want you to.

The last part:
Minor bug fixes/tweak for compatabillity reasons, such as altering the dependancies line in info.json to force a load order in a modpack.

Allow you to do just as little as possible.
Also I don't think you could reupload the mod to the portal even under that last sentence.

For the Github part Ill add the github repo with the next update, sorry for my english

That license says that you can redistribute modified mod versions if you get an expressed permission from Bob.

Well yeah but that is still closed source if I can not contact bob then I can not reuplod the mod.
If I get the autorization of Wube to redistribute an altered version of the source code of factorio that does not change the fact that factorio is closed source.

The license that this mod is under states that you can edit and repost the mod without limitation and without letting me know, you just need to tag the original work and use the same license.

Also from what I understood bob's mods are already under a kind of community maintance but don't quote me with this information because it is most likely a misuanderstanding from me or my source.

If you have any suggestion about how I can change the statement in the frontpage Ill'be glad to hear it

Also from what I understood bob's mods are already under a kind of community maintance

Yes, this is correct. Bob has pretty much retired from modding. The code is up on GitHub now, for anyone to submit PRs to. The license just prevents the mod portal becomes littered with clones that just change one setting etc.

Having high quality alternatives to QoL is a good thing! (E.g. FNEI vs Recipe Book. Helmod vs Factory Planner). Having multiple forks of the same mod isn't great imho.