GCR broken under 3.38/nightly runtimes
Not quite sure when this started, but GCR is broken when running 3.38/nightly runtimes:
[deb] 20:33:49.0203 Gcr:starting initialize of registered modules
[deb] 20:33:49.0208 Gcr:completed initialize of registered modules
[deb] 20:33:49.0208 Gcr:trust store uri is: (null)
[deb] 20:33:49.0208 Gcr:trust lookup uris are: pkcs11:library-description=PKCS%2311%20Kit%20Trust%20Module
*[wrn] 20:33:49.0208 geary:application-certificate-manager.vala:74: No GCR slot URIs found, GCR certificate pinning unavailable
With no (writable) trust stores, it's not possible to use GCR for pinning certificates in applications that use it for that (such as Geary).