In a SharePoint document library, we want to be able to retrieve, open or download a previous document version, without reverting back that version as main (restore).
If we go to version history, we can right-click the version number and click "open in new tab".
This action will cause the browser to atually open the document directly.
If we look at the URL, we can also understand that we can manually go there, in case the browser's display form is failing for some reason, using _vti_history and 512 increments.
http://website/sites/sitecol/_vti_history/512/doclib/sample.docx - version 1.0
http://website/sites/sitecol/_vti_history/1024/doclib/sample.docx - vesion 2.0
http://website/sites/sitecol/_vti_history/1536/doclib/sample.docx - version 3.0