Created attachment 78902 [details]
file with non generic values in the draw:name attributes

The values of the attribute draw:name in the element draw:equation are lost on import. If the opened file is saved they are replaced with the generic names f0, f1, ...
 
That is bad behavior, because
(1) another application might use the names
(2) it makes maintaining custom shapes more difficult.

At least if the draw:type element has a value different from 'non-primitive', which indicates that this custom shape is used by a special engine, these values should be preserved.

I can confirm the reported effects without understanding 

Steps how to reproduce:
1. Open Sample document
2. Save from various OOo, AOO, LibO versions
3. Compare "content.xml" of all saved documents, result below!

Source document in document code lines 30 (app.) and following contain terms like
<draw:equation draw:name="Startwinkel" draw:formula="$0" />
where user defined strings like "Startwinkel" change: 
<draw:equation draw:name="f1" draw:formula="width/2"/>
in saved documents

ISO/IEC 26300:2006(E)© ISO/ v1.0 (ODF1.0) where already several specific rules for the strings (may not contain spaces), so it's sure that it's intended t allow user defined names, and because of reasons Regina mentioned it's not a good idea to modify such names. For Impress documents this might be less important, but for spreadsheets and texts I saw several applications where other software processes ODF documents (simply using these documents as "Data Storage Containers" with standardized structure, and there it would be fatal if suddenly the other software suddenly finds modified Names. So AOO should generally avoid changing such allowed user defined names.

This is not a new problem, I already see that with OOo 3.1.1, OOo 2.0

I can't see where the user defined names become lost, may be during open-import as reported, may be not when the document becomes saved.