While most of the brands offer a consumer-friendly bootloader unlock option and tools, Nokia want their devices to be locked forever.
When asked about support for Unlocking Bootloader, Juho Sarvikas Chief Product Officer at HMD Global replies "Sorry, we wont unlock it due to security however we will share our kernel modifications back to the open source community, wip".
Seriously? In other words he's saying "You can have kernel source so you can develop Custom ROM but we wont let you unlock the Bootloader to flash them". Hope this changes in the future as it's really disappointing for those of us who may have wanted to Root, flash a custom ROM or kernel onto the device.