`git log --graph --decorate --oneline` is specific to a branch of a repository. Github Network shows the relationship between forks. It is similar but really the question answered by it is "what and where is the work being done" and "what is the relationship between work being done and this repository I'm looking at". It sucks that Network is buried, I think it should be much more accessible.

Eg https://github.com/sindresorhus/delay/network tells me that this work is being maintained actively, but most forks are not merging back. Another one might tell me work on the main fork is stalled, and many users are now doing PRs against a fork of the original.