It was also somewhat important (but not at all required) since 300/400-level classes used a lot of Linux-based lab machines and this taught you how to get around if you weren't comfortable with them. Before that, most work was done [when I was there] in cross-platform IDEs and just paper/pencil (proofs, maths, and such), so I remember this coming a bit later for that reason.
It also used to be called 303, which made a bit more sense when I was there in the context of being an early 300-level class to get you primed for the later ones. UW CSE went through a big renumbering and restructuring the year I graduated so I don't fully know how it fits in anymore.
Since I took it, it looks like they've added Git and removed a C, gdb, and Make which is a bit sad, but probably more practical...
I'm sure a lot more changed. Fun to see this pop up, though!