Hi all,
My name is Colson and I am a Senior Support Specialist at HubSpot!
I believe I’ve found a custom reporting solution that may work to meet this use case within the custom report builder. If you take a look at my screenshot, we can use “Marketing email activities”, as well as “Count of opened emails” and “Browser family” to get a report of marketing email open activities up to 1860 days in the past:
If this meets your use case, feel free to mark this post as the solution until there is an actual update from our Product team on whether not a more “native” solution will be implemented on our future roadmap!