The CTAF information was added internally to the VATSIM AIP in 2020, and each facility has the power to “assign” a CTAF frequency for any airport they control.
In the interest of avoiding confusion, the CTAF information was only presented to airports that are part of the trial on the API, so even if a facility outside of the trial assigns a CTAF frequency to an airport, it will not be displayed as such on the API.
The issue is that I was not aware that the frontend was showing this information, since it hasn’t changed since it’s initial inception in 2020. I’ll make that adjustment