If you hover over them the full time shows up as a tooltip at least.
Adding different resource identifiers to the url can also retrieve different commit formats:
Email Patch: https://github.com/rails/rails/commit/b83965785db1eec019edf1...
Unified Diff: https://github.com/rails/rails/commit/b83965785db1eec019edf1...
And I have a rant about that: I wanted to see the date when that commit was done. But all it says as "date" is: "a year ago".
Why? Why can it not say the actual date? "A year ago", what does that mean? I want to know which month and day, even the time!