@lfryc It's wrong because even tho it's a WAR file it might not be of type WebArchive. 

It might be e.g. MyCustomBusinessWebArchive or what ever else the user found in his interest to create. 
Or ESBWebArchive.. etc etc.. 

All containers rely on archive name extension so.. so should we. Arquillian Core just changed to avoid relying on Types:
https://github.com/arquillian/arquillian-core/commit/67fa66e4f5440b88148a95658047c33eaa893aea