https://www.esoui.com/forums/showthread.php?t=9865
Provides info about how to request updates of addons.
In short:
Pm author
Wait
Post content at the addon comments and provide the author the files you have changed there.
If he does not respond within 2 weeks:
create your own patched version and release it like described at the thread linked above.
Use the original addons website, click on other files, click on upload patch/addon (only shows there if the author enabled it! So if it's missing there the author dislikes patches and you should not upload any).
Or if you do not want to do this as you do not want to be an addon author: just provide the patched version files as a zip archive download link at the addon comments of the original addon so others can use it if they like to, and the dev can use and incoporate it later on as he gets back and sees it.
Always check in advance if the addon uses a license and if your are allowed to create patches and distribute it.
If the license disallows changes of the files please respect it and do not populate your changed files, just use it locally for yourself then. But feel free to send the pm to the author asking if he is interested in your code changes.