# Return all prefixes declared (and undeclared) in this context.
	#
	# The empty (default) prefix will be included in this
	# enumeration; note that this behaviour differs from that of
	# `prefix`, `prefixes` and `prefixes_of`.
	#
	# SEE: `prefixes`
	#
	# SEE: `uri`
	fun declared_prefixes: Collection[String] do
		return current_context.declared_prefixes
	end