This is a —a compressed, cracked version of GTA 5 distributed by an unofficial group or individual using a pseudonym "Highschool Technical." The "Gamerrar 1" suffix suggests the file was packaged using WinRAR (or similar archiving software) and is version 1 of that particular release.
The file did not download completely, leading to archive corruption. The password is case-sensitive, or includes hidden spaces. Review of Recommended Solutions
to see if you get a specific "checksum error" or "corrupt" message instead. GTA 5 System Requirements
Some repacks have a custom launcher ( Launcher.exe or Play.exe ) that asks for a password before starting the game. That password is from the archive password and is often:
Blocked Drains Reading