Here is below a simplified representation of the internal structure of a CEL. Basically, for a given event, and for each component (Digi, Recon, ...), one will find the index of a file, and the index of the entry to use from the tree in the file. There could be a single collection of filenames. Yet, so to ease and speed-up the merge of CELs, the filenames are split among several sets. There is an additional tree of links, which says which set to use for eahc event.
