Transient became part of which Emacs release?

[doolio]

The transient.el header states "This file is part of GNU Emacs." but which Emacs release was this? I ask as I am trying to extend another package and wish to use transient as a dependency. This other packages supports at a minimum Emacs 26.1 and so I think my extension should do the same. With that do I need to list transient in my "Package Requires:" line?

Thank you for transient and your time.

P.S. I did quickly scan the release notes here but didn't see it explicitly mentioned.

[tarsius]

It was added in 28.1, but you should just add (transient "0.4.3") to Package-Requires anyway, to ensure the latest version is installed (which after this weekend will be 0.5.0).

[doolio]

Perfect. Thanks Jonas and for the quick response.