I think human intervention has occurred in some of those examples. The Char names are a carryover from older versions of the Word bug you obviously know about. Another Word bug is responsible for the appended digit sets hanging off a parent eg Head1 created for a valid reason then spawned "Head11,Head12,Head13,Head14". I most often see this in table styles but these look like they follow the same pattern.

I would say the shorter aliases like "Head1, H1" were placed there by an author wanting to type a style name shorter than "Heading 1".

And finally, there are other aliases that are appended to built-in styles for the purposes of merging (rationalising) styles. I would surmise that "Part" and "SCE" fall in to that category.

The reason you are seeing these complex stylesets is that nobody ever works from a blank piece of paper. Everybody copies and pastes from older docs and formal government SoWs are beasts that have ancestry dating back 20+ years. The aliases get (asexually) transmitted whenever you paste (or insert from building blocks) content with 'infected' styles from any word source. It is so very easy to re-infect a document, it is no wonder that the very few people who know HOW to clean up the styles just don't bother.

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Andrew Lockton
Chrysalis Design, Melbourne Australia