assembling some links: since the 20th Dec’2024 there’s a tarball at HMD official GPL-sink for the Skyline (seems “tomcat” is the codename)
https://www.hmd.com/en_int/opensource
- see “HMD_Skyline_V1.380.tar.bz2” → packages kernel, devicetree, android-runtime mods, as it’s qualcomm I’d guess you can probably find that source tree at linaro respective kernel-version repo (e.g 5.10) at kernel · GitLab
- besides tomcat, I see buildconfig for other device codenames in the tarball: waipio parrot lahaina
- HMD/Nokia device codename mapping at GitHub - HikariCalyx/hmd-nokia-codename: Codename of HMD Nokia Smartphones / Tablets.
- Nokia Android Dev · GitHub (unofficial, not touched since 2020)
with the kernel you can do at least twrp bringup and flash a GSI