How does UofM calculate high school GPA?

Colleges and Universities A-Z University of Michigan
1

Sorry if this is a common question, but how do they calculate high school GPA?

Unweighted?
Are (+) and (-) included?
What classes count? Only academics? Do electives count? Music? PE (likely not PE).

2

Any A is 4
Any B is 3
Etc

All classes count, but they DO consider overall rigor.