As a PHP developer, I love, but also need to be able to change the extension names of my files.
This little trick can be very useful for anyone who is having the issue of not being able to view windows 10 files extensions.
1 - You need to click on the bottom left search bar in windows 10(the magnifying glass):
Type this command:
Show file extension
As show in the image below:
Click on the top icon called "Show or hide file extensions".
2 - When the popup shows up as shown in the image below:
Click on "View" and scroll down until you see the tick box titled "Hide extensions for known file types"
Make sure that this little box is not ticked!
Click "Apply" and now you should be able to rename your file extensions.