So, as I promised, solution for combining Location Service Extension by Taifun and Itoo extension:
"location_service" - it's my tag, defined in this block:
In this manner I can get list of coordinates, which saved in this tag.
Actually, we can get any TinyDB tag with this solution, just need to define needed Namespace.
JSONToolsVersion4.aix
com.KIO4_GetTinyDB.aix
Thanks a lot to @Juan_Antonio, for unique extension.
Thanks a lot to @Kumaraswamy , for the background tasks!
UPD. 16.06.23. This solution does not work with Location Service Extension by Taifun to get current coordinates. But, it will work with TinyDB, you can get data which written before app going to background. Here the working solution how to get coordinates with Location Service by Taifun.