(Why) I can't send zipped KiCad packages to a gmail mail server

December 31, 2020

Today I broke a pcb manufacturer website trying ot upload a zipped project file using my a KiCad nightly build. They said to email them, when I did, I got a bounce message saying:

host aspmx.l.google.com[] said: This message was blocked because its content presents a potential security issue. Please visit https://support.google.com/mail/?p=BlockedMessage to review our message content and attachment content guidelines.

It took me a few minutes to understand what is happening, eventually I found what I was looking for at the list under "Types you can't include as attachments" and the culprit: .lib

I had a custom footprint in my repository and this is saved as _cache.lib (also -rescue.lib)... But those are plaintext files...

I did a facepaw.