Include annexed file content as part of Pull Request and Fork

**Describe the feature**
I would like GIN to support fork and pull request for annexed file content between repositories.

**Describe the solution you'd like**
I don't have a specific solution yet.

**Additional context**
We are developing a fork of GIN and would like to include annexed file content as a target for forking and pull requests between repositories. Annexed file content is not covered in GIN, is there a cause or intent? And are there any plans to develop this in the future?
If you have any challenges at this point, sharing them with us would be a great help for us.

I found the following similar query, but it had not yet been answered, so I created a new question.
https://github.com/G-Node/gogs/issues/27#issue-396580558
https://github.com/G-Node/gogs/issues/110#issue-782261420

Sincerely.