Jurisdictions which use a title theory in this situation treat a mortgage as an actual conveyance of title until the mortgage is repaid, if not permanently.
From the en.wikipedia.org
Words to that effect may be used by the parties in the deed of conveyance or other instrument of transfer of title, or by a testator in a will, or in an inter vivostrust deed.
From the en.wikipedia.org
However since the introduction of Torrens title in 1858 most land is now under the new system of conveyance.
From the en.wikipedia.org
The title to the land remains in the grantor and the grantee cannot maintain an action for breach of the covenant in the conveyance.