Both were marked 'deprecated' since EAPI 0, and are no different from use/has. useq is used by exactly one package, probably by mistake: net-libs/nfqueue-bindings/nfqueue-bindings-0.5.ebuild: use python || useq perl || die "At least one supported language must be selected." net-libs/nfqueue-bindings/nfqueue-bindings-0.6.ebuild: use python || useq perl || die "At least one supported language must be selected." hasq is not used at all. Let's remove them completely in EAPI 8.
*** This bug has been marked as a duplicate of bug 199722 ***