Sadly, they got released under a propietary license, you can't neither freely share or sell them, nor use the code for your own personal projects. OTOH, you have Calypso and Tristam Island, where the games are written for the Z3 version of the machine with Puny Inform (Something like Inform 6 library 'lite edition' for 8 bit computers), thus, they will run everywhere and you can use the code of both games under the same terms if you want to write your own text adventure.