It seems to me that this airport is significant and should exist in Simbrief. I located this airport in several places on the internet:
MM67
Ingeniero Manuel Moreno Torres Airport
Matehuala, Matehuala MX
Hi,
Thank you for your question …
This airport doesn´t provide scheduled passenger public services—it´s “only” for flight training and GA activities. It is not included in the AIP of Mexico and, therefore, is also not included in any of our sources.
I´m sorry,
Richard