TexMaker (or its forked equivalent: TexStudio) has a dictionary option that provides spelling feature in the editor. However, as mentioned in question Add word to TexMaker dictionary?, there is no direct way to add extra and custom words to its dictionary. This is an important feature especially for those who work in a specific field of science or technology with uncommon words. It seems the only way to add extra words to the dictionary files is to edit them (the dictionary files can be found in the installation folder of TexMaker). Also, it seems that TexMaker uses standard OpenOffice (Hunspell, as mentioned by Tim Hoffmann) dictionaries.
The problem is that there are some codes following words in these dictionaries that apparently help to skip adding variants of a root word. For example, for the word book, we have book/SBJGMD. These codes are apparently defined in the affix (.aff) files that acompany the main dictionary (.dic) files. However, I could not find any description of their meanings in the affix files. I need this information because I want to add some extra words to the dictionaries for my own use without adding all their variants.
Is there any reference about the codes or the syntax used in the affix files?