The "/ckout" page:

Show information about the current checkout. This page only functions if the web server is run on a loopback interface (in other words, was started using "fossil ui" or similar) from within an open check-out.

If the "exbase=PATH" query parameter is provided, then the diff shown uses the files in PATH as the baseline. This is the same as using the "--from PATH" argument to the "fossil diff" command-line. In fact, when using "fossil ui --from PATH", the --from argument becomes the value of the exbase query parameter for the start page. Note that if PATH is a pure hexadecimal string, it is decoded first before being used as the pathname. Real pathnames should contain at least one directory separator character.

Other query parameters related to diffs are also accepted.