LibrePCB specifies a courtyard layer.
The courtyard, according to IPC:
So it seems that there are two “courtyard levels”: The minimum area (maximum boundary + excess) and the manufacturing zone (minimum area + manufacturing allowance).
Should the “Top/Bottom Courtyard” layer in LibrePCB libraries contain the former or the latter?
The way I understand it, the minimum area is based on standards and the actual part and is what we should use. The manufacturing zone is dependent on the manufacturing process, and thus should not be reflected in the library element.
It would be great however if the user could set a manufacturing allowance in the project configuration, which would then automatically be added to the courtyard layer.