How do I find the url for a brew tap?

If you have a tap user/repo, which is not on github, you can get the associated URL in two steps:

1) Go to the location of the tap.

cd /usr/local/Homebrew/Library/Taps/[user]/homebrew-[repo]

2) Use git to check the remote repository

git remote -v

If the tap is on github you can simply make a substitution to get the URL:

https://github.com/[user]/homebrew-[repo]

You can get the repository url by running:

brew tap-info foo/bar