err... wrote about it? this points to an article about Palo Alto Tiny Basic (in 1K) which is a very different basic than Sinclair basic! Its better comparable to the limited Sinclair basic of the ZX80, but SpecBas is the much enhanced basic for the Sinclair Spectrum.
Not that tiny basic on the RPI isn't interesting mind you, I have still fond memories of some of the many "tiny basics" at the time, I remember finding the 8080 source code for one in a German magazine, and porting it to a Z80 self-built machine, (inspired by the exidy sorcerer) of a friend. But there were many more tiny basics you could find left and right, another nameless one I used was written in 6502 assembler for the KIM-1, and came on a roll of papertape.
Then I got a TRS-80 (clone, the LNW-80) I bought after some experience I had with Level 1 BASIC 1 in 4K on a TRS-80 in a Tandy shop. But my LNW had the much expanded (microsoft) Level 2 BASIC. The original Level 1 was based on Li Chen Wangs tiny basic, but not Level 2, which was one of the first Microsoft basics.