Libre Office has a nice feature of remembering where you left off in a document. If you were on page 3 when you last saved the document, it reopens on page three.
I’d like to know where this is saved so that I might reset it. Is the information saved in a config file or directory somewhere or is it saved in the document itself?
The last cursor position is recognized when the user name in the document …
Menu Files → Properties...
General tab
Modified: "xyz zyx"
… is the same name as the user name in the LibreOffice user profile
Menu Tools → Options... → LibreOffice → User Data
First/Last name: "xyz zyx".
"User Data" is stored in your user profile, file "registrymodifications.xcu".
You can remove the user name in the document via
Menu Files → Properties...
General tab
☐ Apply user data (disabled)
OK → Save.
You can also remove the user name in the document via
the unzipped .odt file →
in the file "meta.xml" remove →
<dc:creator>xyz zyx</dc:creator>
Then repack it to an .odt file.
But why?
A much more simpler way to reset the position, is to just open the file, place the cursor at the very top and resave 
Removing the user-data has no impact on the stored cursor position, it only prevents it from being restored when loading the document. (as manj_k mentioned, it is only used when the editor of the document matches the name in the from the user-data in the options)
It is stored in the document - and while removing the creator from meta.xml prevents it from being restored in the UI, the information itself won’t be thrown away. The info is stored in settings.xml in the node and can be requested explicitly using Restore editing view (default shortcut: <shift>+<F5>) even when the user-data doesn’t match up and thus the document opens at the very top.
So if you want to remove it manually from the fileformat, remove the View* related entries from settings.xml but just placing the cursor at the beginning or end and resaving seems so much simpler - so I join manj_k in the question “Why would you want to do that in the first place?”
Awesome
Many thanks to you both. These are by far the most complete, detailed and helpful answers I’ve ever received from this board.
To answer your questions as to why… After a few years I have countless folders full of documents and spreadsheets from the past, some quite large. They all open at the end