This could be an early-stage (v0.1) PC port or a specialized ROM/utility for Atari enthusiasts or hardware developers.
"HSBR" is a technical setting in the Altirra Hardware Reference Manual (Atari 8-bit emulator). HSBR-0.1-pc.zip
It stands for Horizontal Sync Begin Register , which affects how character cells and horizontal blanking are handled in vintage computer emulation. This could be an early-stage (v0