How to add custom app tasks in ubuntu activities search ? What is the specific term for that search bar?

search 20.04 activities-overview

These results are provided by a Gnome Shell search provider. From Gnome Developper Documentation:

A search provider is a mechanism by which an application can expose its search capabilities to GNOME Shell. When the user types anything in the shell’s search entry, the text is forwarded to all known search providers, and the results are relayed back for display.

The link introduces how a search provider is implemented.

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