`git help svn` does not mention `propset` but it does mention `proplist` and `propget`. This seems like an oversight.
$ git help svn
...
proplist
Lists the properties stored in the Subversion repository about a given file or directory.
Use -r/--revision to refer to a specific Subversion revision.
propget
Gets the Subversion property given as the first argument, for a file. A specific revision
can be specified with -r/--revision.
...Interestingly, the generic `git svn` help does mention `propset`.
$ git svn
...
propget Print the value of a property on a file or directory
--revision, -r <num>
proplist List all properties of a file or directory
--revision, -r <num>
propset Set the value of a property on a file or directory - will be set on commit
...
It seems Documentation/git-svn.txt is missing text for `propset`.- Joe