How to save a pdf file in a browser window without downloading it again? Typically on my Macbook Pro, I click on URLs to pdf documents and they open in a browser window (say, Safari or Chrome), and later if I wish to keep a copy of the pdf file, I click the down arrow icon.

However, the down arrow icon actually attempts to fetch the pdf file from the server again, whereas I already have a local copy in a browser cache somewhere. So, it is an inefficient use of bandwidth. Furthermore, sometimes the original file may no longer be available at the server, or I may not be having Internet access, etc., and I want to save a copy of the file.

Do I need to go searching for the file in the browser cache somehow? Or is there a more convenient way?
If you have a PDF file in the browser window you can just go to the File menu and save the file. It will save as a regular PDF and you can choose where to save it.