SlackBuilds.org

Search types:
- Reverse Dependency (1 level) finds dependees: builds that list the search
 term as a dependency. If you search for "foo", every build that lists "foo"
 in its .info REQUIRES will be listed. Only exact matches are supported. Note
 that optional dependencies (mentioned in README, not REQUIRES) are NOT
 searched for. If you're about to update one of your builds, this will tell
 you what other builds might be broken by your update. It's polite to test
 these builds against your update, or at least notify the maintainers that
 they should check them.
- Reverse Dependency (full) works like 1-level, but recursively finds each
 dependee's dependees, up to 10 levels deep. You might be surprised how
 many other builds ultimately depend on yours...
- Maintainer Name/Email lists all builds maintained by the name or email
 address you enter. Matching is case-insensitive. Partial matches are
 supported, so entering "Joe" would find both "Joe Smith" and "Joe Jones". It
 would also find "joe@example.com" or "someone@joe.org".
- Download/Homepage URL lists all builds whose HOMEPAGE, DOWNLOAD
 or DOWNLOAD_x86_64 match your search term. Partial matches, case
 insensitive. If a site that hosts a lot of sources (e.g. github.com, sf.net)
 were down, or had restructured its URL scheme, you could quickly find all
 the builds that would be affected.