The 2020.02u1 release comes with a broken PDF for the Validation Language.
Where can I get a working copy?
There should be a working link to all the latest (BA) documentations on the QA server: <INTERNAL_LINK>
You can find the one for the validation language in particular here: <INTERNAL_LINK>
Current documentation of the Validation Language can be fond on geta12.com. This currently covers the 2021.06, 2022.02 and 2022.06 release versions. The documentation can be found under Modelling → Basic Modelling → Validation Language