The tracer version currently used in Appstream seems to be not supported for Oracle Linux and checking for packagemanager history will return empty.

Tracer has added support for Oracle Linux starting from version 0.7.9 - FrostyX/tracer@6b02b27.

RHEL support was already present in 0.7.5 and hence the RHEL 8 AppStream repo points to 0.7.5 but i think Oracle 8/9 Appstream should point to >= 0.7.9.