Overview of how to build an “Actions/Activity” feature like the one in trello, where all actions are displayed in a last in time descending order

If I wanted to build a feature into my app as the one in trello where the latest actions of the team are displayed in a list order in descending (time). How would you design such a system to track actions?

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As a musician, how to add a song to Google Assistant’s song recognition feature?

How would an independent musician add a song to Google Assistant’s song recognition database?

Does Google Assistant pull data from an open music database such as AcoustID/MusicBrainz? Does it pull from a proprietary database like Google Play Music? Or is it something proprietary, internal to Google, and unknowable?

Mojave Stacks feature: More specificity for grouping

I am trying to use Mojave’s new Stacks feature that can group files on the desktop. I have it set to group by “Kind”. It created a stack called “Documents”. But the contents are very heterogeneous: this stack absorbs everything from Markdown documents through Mathematica notebooks to MS Word files.

I would much rather have these types separated. Is this possible?

For my use case, it would be sufficient to make the system consider Mathematica notebooks not to be “documents” (and let it mix the rest of the types).