While still highly experimental and quite a hassle to setup legitimately, the Nintendo Switch emulator yuzu is still another fine example of open source. It's a very capable emulator already too, with it being possible to play through an increasing number of games.
On the Linux side, dependency issues and getting it running hasn't exactly been easy but they've partly solved that now as they've announced they're providing an AppImage for all releases going forwards. So for all you big emulation fans, that's going to make playing with each release a whole lot quicker and easier.
Going by the latest progress report from January work is going well with multiple more games now actually able to boot up including Katana ZERO, DELTARUNE Chapter 1, Dragon Ball FighterZ and Wonder Boy: The Dragon’s Trap.
Unsurprisingly yuzu has proven to be very popular, with their Patreon campaign pulling in very close to £13K per month. Emulation is important though, most people know and understand this by now. Companies eventually move on and this projects help keep them alive. Hopefully over time the getting started guide will have far less steps, but don't count on it being too easy until Nintendo moves onto their next console. They gradually make small steps on this though, like recent work to integrate new OSS fonts so that you longer need to dump the Switch firmware to get proper button fonts.
There's a colossal amount of work going into this every month, with tons more planning including Vulkan performance and stability improvements and ongoing overhauls to the yuzu Kernel (what makes everything tick).
yuzu isn't the only open source Nintendo Switch emulator around, there's also Ryujinx although the setup isn't really any easier there either.