Because when you download a file from the internet, and you don't have an application to open it, you can go to Open with AppStore option and what happens is that AppStore will show you which app has your file extension in their plist file (in our case Open Any Files: RAR Support. How to open any Mac app or folder with custom shortcuts. Click the menu under Predefined Action, type file in the search field, and again choose the Open Application / File / Apple Script sic. How to find downloads on your Mac in a web browser If the browser where you downloaded a file is still open, you can pull up the download right then and there. In Google Chrome, click the three.
Safari User Guide

Download music, PDFs, software, and other items by clicking links on webpages.
Open Windows File On Mac
Important: If a download contains software, an alert appears when you open the item. To be safe, don’t open it if you weren’t expecting a software program or if it’s not from a trusted source.
Download an item



In the Safari app on your Mac, click anything identified as a download link, or Control-click an image or other object on the page.
Choose Download Linked File. (Some webpage items can’t be downloaded.)
Safari decompresses files such as .zip files after it downloads them.
Note: If you download an item that you previously downloaded, Safari removes the older duplicate so it doesn’t take up space on your Mac. See Optimize storage space on your Mac.
See items you downloaded
Open Any File Mac Download Mac
In the Safari app on your Mac, click the Show Downloads button near the top-right corner of the Safari window.
The button isn’t shown if the downloads list is empty.
Do any of the following:
Pause a download: Click the Stop button to the right of the filename in the downloads list. To resume, click the Resume button .
Find a downloaded item on your Mac: Click the magnifying glass next to the filename in the downloads list. If you move a file or change the download location after downloading it, Safari can’t find the file.
Tip: To change where downloaded items are saved on your Mac, choose Safari > Preferences, click General, then click the “File download location” pop-up menu and choose a location.
Clear the downloads list: In the downloads list, click Clear. To remove one item, Control-click it, then choose Remove From List.
By default, Safari automatically removes an item after one day. To change when items are automatically removed, choose Safari > Preferences, click General, then click the “Remove download list items” pop-up menu and choose an option.