Install arbitrary apk from filesystem on Android 10?
To disable /enable this permission :

Settings &rarr; notifications&rarr; Special app access&rarr;
 Install unknown apps &rarr;your app

AFAIR, this change came about from Oreo (Android 8)

Solid explorer and Mixplorer are the one's I use and they both install apk's (OnePlus 7, Android 10)



(From Mixplorer - click to enlarge)