[caribousoup]

This was in 2018, not sure which version. UTF-8 across the board.

I don't remember the details, unfortunately. I think there was a pattern to it, like they were control characters or something. But it silently inserted them, and they were not visible within the editor, but they were visible in nano/less/etc.

[zyedidia]

Did they just appear as space characters, or did they actually not take up any cells in the editor? Currently some non-displayable characters are rendered as spaces, which is not ideal. I will look into displaying non-displayable characters in a special way (perhaps as `^@`, similar to how Vim does it, or with �, which is meant for this purpose).

[caribousoup]

I think they were appended to the end of each line, so unfortunately that would make it non-obvious that something was there. If they were rendered as spaces that would explain not being able to see it. Displaying them as � would be an improvement.

Again, this was awhile ago, but I don't think they were single characters, it was a sequence of characters.