This is interesting for information only because you have generally no use for it.
The extension (this is how the “suffix” is technically named) is an artefact historically used by older OS’s to launch the “correct” application when you double-click on a file icon. The association between extension and application is stored in a system dictionary. This dictionary can altered by user to divert handling to another application. The trick is used so that M$ Office documents (Word, Excel, PowerPoint, …) are opened by LO (Writer, Calc, Impress, …) when the M$ suite is not present on the computer.
Newer OS’s have a more elaborate procedure. They first read some piece(s) of the file and try to guess the contents type (this is called a MIME category). The MIME category then determines which application to launch. On these OS’s, the extension/application association list could in principle be ignored. However most of them use a mixed strategy.
To make things more complicated, LO does not rely on the extension. If the OS has determined it should launch LO to handle the file, LO starts by reading the beginning of the file to see what exactly is inside and will route the file to its appropriate component (Writer, Calc, Impress, …). This means that if a naming error has been done on the file (say, you named a text document x.ods), LO will correctly pass the file to Writer and not to Calc. It also means that LO doesn’t really care for extensions.
The only case where this strategy is defeated occurs when LO is confronted with an empty file. It falls back to the extension designation. This case is frequent under Windows, because you can create new files from the file browser without ever being touched by LO. Consequently, the file is not initialised (even a blank file has some contents) and this causes unexpected problems when the file is subsequently opened.
Rather than assigning yourself extensions to file, use the LO components to create your files. When you save, don’t enter the extension. LO will add it without error.
Next rely on the icon on your desktop. Every component has different icons (and icons are also different for various file types like regular documents or templates).
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