I think it was tested before.
I am sure you already have an OpenPLi 5 build.
Make the modifications to meta-openpli/recipes-multimedia/exteplayer3/exteplayer3_git.bb
Then add that file to git (stage for commit)
git add meta-openpli/recipes-multimedia/exteplayer3/exteplayer3_git.bb
Then commit that file locally
git commit -m "exteplayer3: build with flv to mpeg4p2 remuxing support"
# or just commit and write more in editor
git commit
Then create the patch
git format-patch -p1
Upload the patch here, or create an issue on github and attach patch
Or simply push to your github fork and use github UI to create PR.
git checkout -b featureBranch
git remote add my_git_hub_username https://github.com/my_git_hub_username/openpli-oe-core
git push my_git_hub_username featureBranch
Wavefield T90: 0.8W - 1.9E - 4.8E - 13E - 16E - 19.2E - 23.5E - 26E - 33E - 39E - 42E - 45E on EMP Centauri DiseqC 16/1
Unamed: 13E Quattro - 9E Quattro on IKUSI MS-0916