For plugins that compute buffer content, it would be useful to associate data with the buffer content that isn't visible in the text.
For example, SublimeTODO abbreviates file names that contain to do items, and for jumping to the right spot, it would be good to store the unabbreviated file name somewhere.
And Tablist shows tabs by their names, but since multiple tabs can have the same name, it would be good to associate the view identifier with each line.
And Dired shows files, but for easier parsing it would be good to associate the complete file name with each line.
It would be nice if there was an API that allowed plugin authors to associate data with a region in the buffer.
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