CSS (green background if selector was applied):

[a\:foo]

@namespace aria ...; [aria|foo]

.getAttribute('a:foo')
Script didn't run
.getAttributeNS('...', 'foo')
Script didn't run
a:foo='bar'
Script didn't run
setAttribute('a:foo', 'bar')
Script didn't run
setAttributeNS('...', 'a:foo', 'bar')
Script didn't run