When the recipient creates a temporary WT instance (to rollback-to-stable the donor files and record collection metadata), it calls wiredtiger_open with a config string. There are configuration options that might vary on the donor which the recipient must match, like "compressor=snappy". Figure out how to match these up, e.g. the donor sends a config string to the recipient via the recipientSyncData command, and the recipient stores the string in its state machine.

See: https://github.com/10gen/mongo/blob/0d3e3f270117064349f27e814dd27156dc1bdbb5/src/mongo/db/storage/wiredtiger/wiredtiger_import.cpp#L162-L166