Bernard visits this level to use an older computer system. The Woodcutter, an early model host, strayed from its loop to transmit stolen data to a Delos satellite outside the park. Bernard wants to access the legacy data (information stored in an old or obsolete format or computer system) about this host, and specifically its legacy GPS information. Westworld's new system cannot read the legacy data, so that is why Bernard travels to floor B82.
"The old hosts used a legacy geopositioning system."
While there's limited lighting on this level, and it's in some disarray, he manages to find a working computer and retrieve the data he wants (the exact time that the Woodcutter was in and near the crevasse in Python Pass). He also finds that there are five hosts in the park that aren't registered with the new system.