If anything, that talk was a tad low effort, with even dismissive answers — "Yes" and "No?" as full answers to audience questions, with no follow up?! Still very informative though!
It's a very "I've made a cool thing. This is what I think is cool about it" type of talk. Which I don't think is uncommon for FOSDEM. Maybe a bit uncommon for a higher profile figure like Lennart.
He held a similar talk at All Systems Go I think (I missed the talk here at FOSDEM).
> It's a very "I've made a cool thing. This is what I think is cool about it" type of talk.
Varlink isn't something he just made up, he mearly "adopted it" (started making use of it). It existed before, but I don't know anything that really made use of it before.
The official-looking website at https://varlink.org doesn't give any information about who the authors are, as far as I can tell, but the screenshots show the username "kay". There's a git repo for libvarlink [1] where the first commits (from 2017) are by Kay Sievers, who is one of the systemd developers.
An announcement post [2] from later in 2017, by Harald Hoyer, says that the varlink protocol was created by Kay Sievers and Lars Karlitski in "our team", presumably referring to the systemd team.
So the systemd developers "adopted" their own thing from themselves?
[1]: https://github.com/systemd/systemd/commits/main/?author=kays...
[2]: https://github.com/search?q=repo%3Asystemd%2Fsystemd+varlink...
If Lennart Poettering "adopted" varlink, he seems to have done so from members of his own team ("our team") who created varlink and who are also fellow co-creators of systemd.