It depends on the level of the CRB check and there are 3 different kinds.
Level 1 shows unspent convictions/cautions (although cautions are now spent as soon as issued).
Level 2 shows all convictions, cautions, reprimands and final warnings, spent or unspent.
The super-enhanced CRB check will have the same along with details of any contact you’ve had with the police, whether charged or not. This one is reserved for people applying for jobs with children & vunerable adults though.
Again though they aren’t that accurate on the enhanced. I know of several people who don’t have their previous cautions show up on enhanced CRB’s