(author here) Just a 32 entry BTB is technically a possibility from microbenchmark results, but the EIC7700X datasheet straight up says:

"a branch prediction unit that is composed of a 32-entry Branch Target Buffer (BTB), a 9.1 KiB-entry Branch History Table (BHT), a 16-entry Return Address Stack (RAS), 512-entry Indirect Jump Target Predictor (IJTP), and a 16-entry Return Instruction Predictor"