You can export allocations with this kind of command:
xcrun xctrace export --input my-trace.trace --xpath '/trace-toc/run[@number="1"]/tracks/track[@name="Allocations"]/details/detail[@name="Allocations List"]'
xcrun xctrace export --input my-trace.trace --xpath '/trace-toc/run[@number="1"]/tracks/track[@name="Leaks"]/details/detail[@name="Leaks"]'