Some file formats (e.g. html, png) will be viewable in your browser, and will appear as clickable links below that will open the file once you've fully extracted your archive. Other file types can be opened by their approrpiate applications by navigating through the archive's directory. You can click on any folders that may be present to see their contents.
Below are all the possible formats you could have received in your archive:
Location History
Location data collected while opted-in to Location History.
Semantic Location History
Semantic location history consisting of inferred place visits and activity segments.