Thanks for your comments! CL stands for 'classifier'. This is not really a new 'feature', but a nice addition from the guys working on the CC-CEDICT, the open project Chinese-English dictionary which Xiaoma Cidian is based on.
Here is the explanation from the CC-CEDICT documentation:
Classifiers (also called “Measure words”) can be listed using the following syntax:
避風港 避风港 [bi4 feng1 gang3] /haven/refuge/harbor/CL: 座[zuo4],個|个[ge4]/
Classifiers follow the 'reference' syntax, are prefixed by 'CL:' and separated by a comma (no additional spacing).
The classifier words itself can be described using:
/classifier for small round things (peas, bullets, peanuts, pills, grains etc)/
Btw, some more features upcoming this week to Xiaoma -- stay tuned