Assertions have been renamed to "rules" in ADL2. However, all around the text there are still multiple references to assertions (I believe that even in the grammar). In fact, and probably due to changing the anchors targets, links like "[Assertions]" in rules section seem to be broken (see http://www.openehr.org/releases/AM/latest/docs/ADL2/ADL2.html#_rules_section)
As per our decision last week in Stockholm, we will re-engineer the rules concept for openEHR to be in the BASE component, so that both AOM2 and GDL can re-use the core and add elements that they need.
Good to know, we will also be working on the archetype part of the rules