Evenprime/Bukkit — comment on commit 1aafa6cdc3385b4a644e87a00be6b4f1f6e494ff
File: src/main/java/org/bukkit/permissions/PermissionAttachment.java line 94
By Evenprime:

Directly writing the permission into the map here, because "setPermission(...)" would do "recalculatePermissions()" at the end, which we do directly after this line anyway. So we save one full recalculation of all permissions of the player this way.