I found it generally useful in buildbot days when you could chop-off the buildername in a builder's url (eg: remove "chromeos-amd64-generic-rel" in https://luci-milo.appspot.com/p/chromium/builders/luci.chromium.try/chromeos-amd64-generic-rel) and that would take you to a list of builders for that master (eg: https://luci-milo.appspot.com/p/chromium/builders/luci.chromium.try would give you a list of builders in the luci.chromium.try bucket)

Sadly, that url 404s:
https://luci-milo.appspot.com/p/chromium/builders/luci.chromium.try

The correct url for listing builders in that bucket appears to be:
https://luci-milo.appspot.com/p/chromium/g/luci.chromium.try/builders

Given how similar they seem to be, could we have the 404 just redirect to the correct url? Though I wouldn't be surprised if there's a whole lot of hidden assumptions in that magical "/g/", so feel free to wontfix.