microG is a free and open-source software provided by European developers which published on Github (https://github.com/microg). Some applications rely on microG to run properly. It allows Android applications to access the Google service.

Since 2017 micorG has been widely used in multiple open source Android operating systems. Currently, microG is supported on more than 200 devices from Google，Samsung，OPPO, Motorola and other makers.

For more information you need, you may refer to microG official website or microG webpage on wiki:
https://en.wikipedia.org/wiki/MicroG
https://microg.org/