Kathleen Kennedy is the president of Lucasfilm. She’s executive produced television content featuring Boba Fett, among many other film and television projects throughout her long career.

From her 2022 interview with Vanity Fair:

It’s pretty obvious Jon has an interest in that other Mandalorian since he wrote The Book of Boba Fett. Was Fett his initial idea for The Mandalorian?

No. He was certainly intrigued by Boba Fett. He knew that we were working on Boba Fett in the feature space for a while. So when he started to develop The Mandalorian, there’s no question that there was a lot of conversation around: How do we separate the two? If we were ever to do something with Boba Fett, what would that mean?

Was The Book of Boba Fett similar to those previous ideas Lucasfilm explored as feature films?

We didn’t really get too far down the road on what we were going to do in features with Boba. As you know, with development there’s a lot of things that get talked about and don’t necessarily move forward—or they move forward and they hit a wall. It’s a difficult process. So no, we never got to a point where there was anything that Jon either used or rejected.