What do Stereotype Constraints do?

[Jayson]

Hey guys

Looking at the MDG document [p.39] which is also replicated here: https://sparxsystems.com/enterprise_architect_user_guide/15.2/modeling/definestereotypeconstraints.html

It talks about defining constraints, but what are these constraints used for?
Are they tied into the Add In model Validation Events or something?

Jays :-)