The predictive completion Texinfo support automatically creates and updates dictionaries of node names, dictionaries of locally-defined Texinfo commands (defined using ‘@macro’, ‘@rmacro’ or ‘@alias’), and a dictionary of flags (defined using ‘@set’), for each buffer.
All these dictionaries are saved to the directory specified by predictive-auxiliary-file-location (see Miscellaneous Options), so by default they will be saved to a .predictive/ subdirectory of the directory containing the Texinfo file. They are given a filename of the form dict-texinfo-type-filename.elc, where type is the type of dictionary (node, local-texinfo, or flag), and filename is the name of the Texinfo file.
To speed up loading of predictive mode's Texinfo support, a file containing information about the location of different regions within the document is saved to auto-overlays-filename also located in predictive-auxiliary-file-location.
It is safe to delete any of these files, or even the entire predictive-auxiliary-file-location directory, as long as the corresponding Texinfo file is not loaded in Emacs at the time. They will be recreated automatically next time the file is loaded. However, if you delete the dictionary files, you will lose all learned word weights (see Dictionary Learning).