Contributing on a subversion repo (Savannah)

Hello,

I know how to fork a git repo and to submit a pull request to the 
owner.

I would like to be able to do the same for some subversion repo,  
namely to contribute to translations and help files of GNUstep 
applications.

- I know how to check out and creating a branch within svn.
- Because I have not the permissions to  merge or to commit then to 
the trunk HEAD - what I understand - I would like to know how I could 
submit some minor changes: I tried first 'svn diff' to create a patch, 
but not all the changes were handled.
- I thought I could also create a whole tarball of my branch and send 
it by mail: is it a good matter to do that?
To sumarize, what are the good practices to contribute on subversion 
repo like on Savannah?

Regards,
Patrick

-- 
Patrick Cardona - Pi400 - GNU/Linux aarch64 (Debian 13.1)
Xorg (1:7.7+24) - libcairo2 (1.18.4-1+rpt1 arm64)
Window Maker (0.96.0) - GWorkspace (1.1.0 - 02 2025) - Theme: AGNOSTEP 
- MUA: GNUMail (1.4.0)