For what it's worth, tukaani is how you spell toucan (the bird) in Finnish, and Lasse is a common Finnish name; the site being previously hosted in Finland is very plausible.

Yeah according to their website[0] it looks like majority of the past contributors were Finnish so nothing odd about the hosting provider. On the same page it says that Jia Tan became co-maintainer of xz in 2022.

0: https://tukaani.org/about.html

No:

    route:          5.44.240.0/21
    descr:          Zoner Oy
    origin:         AS201692
    mnt-by:         MNT-ZONER
    created:        2014-09-03T08:09:00Z
    last-modified:  2014-09-03T08:09:00Z
    source:         RIPE

It's Finnish, Oy is short for "Osake Yhtiö" (share-association, basically a LLC), seems to be registered/hosted at https://www.zoner.fi/

So probably Suojelupoliisi, Finnish Security and Intelligence Service is behind all this

Zoner is a Finnish web hosting company, which has a history of providing hosting for Finnish open source projects, and the original maintainer (and most of the original crew) is Finnish as well. Nothing weird here.

Interesting, seems to be a tiny finnish hosting company: https://www.zoner.fi/english/