Previously, routes were of the following format: /file?repo=:repo&id=:id. This isn't very clean and it's not obvious to the reader what it is doing. The design also isn't very RESTful. So the URLs have been refactored to look more closely to the following format: /repos/:repo/file/:id.
The new URLs are as followed:

Getting file blob, checking file existance: 

/repos/:repo/file/:id
Getting a file by commit and file path:

/repos/:repo/commits/:commit/path/:path
Getting the path of a repository:

/repos/:repo/path
Getting all branches:

/repos/:repo/branches
Getting all commits

/repos/:repo/branches/:branch/commits

OR /repos/:repo/branches/:branch/commits?start=:start
Getting a commit (includes the diff):

/repos/:repo/commits/:id
Getting the session:

/session

Verified that all new URLs still return the same contents as their old ones.