Some pages of the Corona Docs are not working, and instead of loading the page it downloads an html file with weird characters on it. Some of the websites I found that are not working:
https://docs.coronalabs.com/api/type/Mask/index.html
https://docs.coronalabs.com/api/type/DisplayObject/setMask.html
https://docs.coronalabs.com/api/index.html
https://docs.coronalabs.com/api/type/DisplayObject/maskScaleX.html
https://docs.coronalabs.com/api/library/display/newLine.html
… and many others