MindTheGapps is a GApps package that is required to be installed on a custom ROM.
Google Apps such as play store, Gmail, Face unlock etc are not part of any custom ROM. MindTheGapps installs basic google apps on a custom ROM.
MindTheGapps is developed by dev javelinanddart for LineageOS ROM builds because OpenGapps failed to be compatible sometimes.
Build info MindTheGapps:
This is the MindTheGapps package build is for Android Oreo 8.1.0.
Build date: 8th August 2018
Supported Architecture: ARM32
This MindTheGapps is available in a zip file format which can only be installed using a custom recovery such as TWRP recovery.
To get these Gapps for other architectures, visit the following page: MindTheGapps for Oreo.