@zep if you open this cart in pico8 and save it, pico8 inserts an extra byte at the end (0xff) (this is wrong, but additionally it is very confusing because my text editor thinks the text encoding has changed and starts displaying weird unicode everywhere)

pico-8 cartridge // http://www.pico-8.com
version 41
__lua__
?'hi'
__meta:title__
cooltitle

After some minimal testing, the conditions necessary seem to be:

1. the file ends with a __meta__ section (__gfx__ doesn't trigger the bug)
2. the file does not have a trailing newline (the last byte of this particular file is 'e', not '\n')

platform: linux / pico8: 0.2.5g

The same problem occurs on Mac OS (Pico-8 0.2.5g)

Seems to add the character ÿ.

Without __meta results in a newline.