I seem to know of two ways to get to where you want to get to (git log --oneline 97dd512) from the page similar to "git show 97dd512" [1].
1. A direct way that requires two clicks:
a. You should click on the 'Browse files' button you see in the page that shows output like git show [1]. Then you'll get to the page where you see the files in the repository just like when you checkout 97dd512 [2].
b. From that page you could click on the number of commits to get to the page you want to see (page which shows output like "git log --oneline 97dd512") [3].
2. A simple but indirect way is to edit the URL when you are in page [1], and replace the 'commit' part in it with 'commits'. This is not a reliable way as there's a possibility that they could change the URL format but it seems to be working well for me so far :-)
Hope that helps.
References:
[1]: https://github.com/git/git/commit/97dd512af7ce4afb4f638ef73b4770921c8ca3aa
[2]: https://github.com/git/git/tree/97dd512af7ce4afb4f638ef73b4770921c8ca3aa
[3]: https://github.com/git/git/commits/97dd512af7ce4afb4f638ef73b4770921c8ca3aa