[MONSTA]

It's a left over from your old OpenELEC installation.

If you install OE fresh, install the OE Unofficial repo (written to /storage/.kodi/addons), then upgrade to LE you'll still have the OE Unofficial repo listed as it remains installed in your addons folder.

If however you install LE fresh, you won't have any option to install the OE Unofficial repo as it doesn't exist within the LE build.

I got it. That's just the renamed OE repo. It was a clean installation. LE image 6.90.004 then your build. No matter.
The transmission service doesn't works, it's important for me. Hope somebody will fix it soon. Thanks.
Regards, Den.