The local copy of the database is kept in ~/Library/Application Support/OmniFocus/OmniFocus.ofocus, which is a package file. Inside you'll find a bunch of zip files, 1 of which contains the compacted database (0000...), a number of which contain client descriptions, and the rest are recent transactions which haven't been compacted into the database yet. The recent transactions are linked together in chains through their file names. You can view one of these files in the Terminal via
Code:
unzip -p <filename> | xmllint -format -
once you have connected to the directory via
Code:
cd "$HOME/Library/Application Support/OmniFocus/OmniFocus.ofocus"
Let the learning adventure begin :-)