Extensions are not supported on mobile currently.

You're talking about this?
https://addons.opera.com/en/extensions/details/scroll-to-top/?display=en

It doesn't appear to have a license which allows modifying the code. You can probably modify it locally for personal use though.

The easiest thing would be to make a report on the above URL and request a feature change from the developer.

There needs to be a persona.ini file in the root of the package, not in a subdirectory. Was this the problem perhaps? If not, if you could put the package somewhere and link to it, we could look at it.

There is a URL based on App ID, actually. We just don't expose those URLs.

https://addons.opera.com/en/extensions/details/app_id/[ID here]/

Sorry. My brain stopped there for a second. Done now.

addons.opera.com detects which language your OS/browser is set to and provides descriptions in that language if available. If you want to change this, you can change the filter language on the search results page.

For example:
https://addons.opera.com/en/search/?query=youtube
There's a box in the top right corner where you can choose a specific language to show results for.
(I get a few search results here, btw)

If the extension is localized in multiple languages, there will be an "Other languages" list on the right hand side on the page for the extension.

Sorry. We currently don't take in any more volunteer languages, as it increases the administration work needed to support them.

Yes. If you go to https://addons.opera.com and click Develop, log in with your Opera account credentials, you can click the button "Submit a new add-on". Here you can upload the zip file of the theme with a persona.ini file in it. The system will normally figure out what sort of file it is when you upload.

You should declare clipboardWrite, even though the extension works without it. The docs states that declaring it is optional for regular extensions, but that it is recommended to do so regardless. This way you inform your users more clearly what your extension does.

Did some more research on clipboardRead and clipboardWrite.

clipboardWrite is optional to declare, but addons.opera.com actually requires it if you use document.execCommand('copy') or document.execCommand('cut'). We could change this, but I'm thinking we want to expose more permission information to the user, not less.

clipboardRead is required if you use document.execCommand('paste'), but we seem to also require it if you use 'copy', which seems to be wrong.