RnOpenGApps is an app for download Gapps from The OpenGApps Project(opengapps.org).

OpenGApps for the following version of Android 8.1 is coming from The OpenGApps Project(opengapps.org) but OpenGApps for Android 8.1 is coming from sourceforge(UNOFFICAL)

And RnOpenGApps is a open source project:
https://github.com/hjthjthjt/RnOpenGApps