This is a fun bug, but not exactly a big deal. I'm not sure if it has been reported before.

If you delete any amount of text at the end of a cartridge, you can retrieve it by pressing the DELETE key while your cursor is at the end of the file (as long as the buffer is not empty).

Simplest way to reproduce: Write something in the PICO-8 code editor, and then delete everything. Write something (one character will do) and then press DELETE. Voila!