Character 26 is CtrlZ, the substitute character in ASCII, which is commonly used as the end-of-file marker in CP/M, DOS, and descendants. (CP/M doesn’t store exact file sizes in bytes, only in 128-byte blocks, so an explicit EOF marker is useful there; DOS did store exact file sizes so it doesn’t need EOF markers.)

Many tools developed for those ope...

would output the file to the screen, relying on ANSI.SYS to interpret the ANSI escapes, and stopping at the end-of-file marker, so the SAUCE records don’t appear on-screen.