sbClient is a SearchBot client for mIRC.
sbClient automatically opens downloaded search results; you can use sbClient to make very fast local searches in downloaded lists and it can group @find/@locator results.
sbClient is capable of automatically requesting SearchBot triggers from channel and can combine results from different search types.
More information is available at sbClient home page.
mUnzip.dll presumably comes from Info-ZIP and is licensed under their own BSD-like license: http://www.info-zip.org/pub/infozip/license.html.