I'm looking for a website with source codes of projects, real life web projects that were leaked or just published because admin chose to not support them anymore. 

I get github exists, but I'm looking for another source.

If you want to audit programs from Sourceforge, you can try that.

GitLab, BitBucket, Sourceforge, etc. If you want something more specific, you could try to crawl DHT's for your query. Other than that, maybe some private trackers but I believe that scene is dead for a long while.

Maybe try using gitlab or github, many interesting projects there

what kind of web projects that you're looking for?

what web projects that you're looking for?

github + stackoverflow

i would also ask what apps you are looking for