When I've used the 'The Clergy of the Church of England Database (CCEd)' I came across those type of abbreviations. The Glossary gives the following explanation, though I don't know what source you are using, so cannot say it means the same for you but it would seem likely.
"Please note that within CCEd ‘liber cleri’ is also used in a slightly different sense. When consulting the summary lists of records relating to a person or place, users of the Database will often note the ‘event’ described as ‘Libc’. On consulting the evidence record relating to such an event, users will see it described as a ‘Liber cleri detail record’. In these cases CCEd has adopted the term ‘liber cleri’ and used it generally to describe a type of record. Original evidence records have been collected for CCEd using a menu of screens – ‘Appointment’, ‘Ordination’, ‘Subscription’, ‘Liber cleri’, ‘Dispensation’, ‘Wills’, and ‘Monuments’. CCEd’s ‘Liber cleri’ screen has been used to enter into the Database all lists of clergy compiled on a specific date. "
