preferred activities

@ xml path
/system/etc/preferred-apps/preferred-activities-home.xml
/data/system/users/0/package-restrictions.xml

@ source code
frameworks/base/services/core/java/com/android/server/pm/Settings.java

@ reference site
https://stackoverflow.com/questions/34073290/set-default-application-on-aosp
https://github.com/opengapps/all/blob/master/etc/preferred-apps/google.xml