Lamb's breath/bread (The variation in name has to do with the Jamaican pronunciation) refers to the best of the native/landrace stuff grown in Jamaica.
The problem is that virtually all grows in Jamaica are done outdoors, and influx of indica and hybridized stuff over the last 20 years has contaminated the genetic pool there to the point where its hard to find any pure Jamaican genetics anymore, even there. Some people who are in a position to know, believe this strain is actually extinct in Jamaica, though there may still be some plants/seeds in private hands outside (and maybe inside) the island. A number of hybrid strains based on Jamaican genetics are still around.
Sannie just released a strain that is allegedly a direct cross of this strain and the famous Columbian Gold. IIRC its sold out, but it might come back.
I'd add that even if you can find some of the original seed stock to start with (which is unlikely), this is a long flowering strain that won't finish before winter time in most of the USA. Indoors, this will be a challenge to grow for new growers, again, because of the stretchiness and long flowering time.