Retrieving security descriptor and getting number for FileSystemRights

Question

Using Get-Acl I am trying to get the access rights on a folder. The thing is, for some groups I get a number instead of a access type. Example below:

Answer 1

Quick and dirty tanslation:

268435456 - FullControl

-536805376 - Modify, Synchronize

-1610612736 - ReadAndExecute, Synchronize

If you want to learn about the translation process this was the best i could find at the moment: Link