Back in the pre-Mac OS X and macOS days, Apple’s System 9 and earlier relied on hidden metadata to associate files with apps. File extensions, those bits of text that follow a period at the end of a file (like .doc, .html, or .jpg) were optional, although often used for compatibility with other platforms and with web. On the web, file extensions are effectively mandatory so a browser knows how to handle a file appropriately.
Macworld reader Rick would like to monkey with that. He has a number of HTML templates, but to differentiate them from his production .html files, he puts the suffix .tt on them instead. Browsers don’t recognize these files by default. There’s a way to force an association between a file type and an application, but that application still has to recognize the extension.
