You can get the files of the port from the FreeBSD git repositories web site. In case of the port in question, the last ports tree including the port would be the 2022Q2 quarterly ports tree. Open the files in a browser (choose 'plain', i.e. Makefile), save files. I suggest to get all files of the port, not only the Makefile, especially the patches under 'file'.
The ports location can be anywhere, a users home directory for example, as long as a updated ports tree is present to use its ports framework.
Open a review at https://reviews.freebsd.org, or less preferred by port committers (as I recall), a PR at https://bugs.freebsd.org. In either way there should be a patch attached, even if it's not complete or doesn't work as expected.
We have a port committer here in forums, zirias@, who maybe want to add to the said.
For documentation, I'm sure you are aware of the Porters Handbook, I mention it here just in case.