Which milestone? M2 changed. No longer uses SCRIPT. Instead Reach language uses it’s own transform service name (e.g. JS for JavaScript, DSL for Rules DSL, etc). It’s covered in the latest docs.
Oh well… So back to how it was. I thought the docs were not updated yet, but apparently it was changed back again.
The sitemap transformations are broken after a restart now aswell. For the thing-transformations every change needs a restart of openHAB though, so changing from SCRIPT:js to JS needs a restart to take effect.