What's the meaning of all indexes in a single treatment?

Question

For the first time, a GLMM model has strange behaviour in the marginal means. I find:

lsm.mTGCp.temp <- lsmeans(mTGCp, c("temperatura"), type="response")
cld(lsm.mTGCp.temp, Letters=letters, decreasing = TRUE)

What's the meaning of abcdef? Thanks in advance!