I have one line in a html file containing a base64 representation of an image. This line spans thousands of lines in the editor, which is a huge hassle when always scrolling past it.
Is there a good way in ST3 of hiding this line?
Select the text you want to hide, then from the Edit menu -> Code Folding -> Fold.
Note that folding is not stored in the session, and reopening the file or ST will display the text unfolded again.
You could also take a look at plugins designed to help you with this: https://packagecontrol.io/packages/Base64%20Fold