CMake: Is there a way to get a list of imported targets that belong to a package

CMake 3.21 introduced the directory property IMPORTED_TARGETS that can be used to get a list of all imported targets. This can be used to derive a list of targets that were imported by a single find_package() call when it is queried before and after the call to find_package(). The code could look something like this:

...
get_property(importTargets DIRECTORY "${CMAKE_SOURCE_DIR}" PROPERTY IMPORTED_TARGETS)

find_package(Qt5 COMPONENTS Core Widgets REQUIRED)

get_property(importTargetsAfter DIRECTORY "${CMAKE_SOURCE_DIR}" PROPERTY IMPORTED_TARGETS)
list(REMOVE_ITEM importTargetsAfter ${importTargets})

message("${importTargetsAfter}")
...

Usually it is good enough to only print the list of all imported targets and guess from the names which of them were imported by the package of interest.