In a conventional environment, uploading and overwriting an existing file would replace the document. However, by adding new fragment IDs to an existing PSML file before uploading and overwriting, the fragments are added to the document without replacing existing fragments.
Likewise, using a fragment ID it is possible to update only a select part of an existing document, say ‘monthly sales figures’, without any change to the rest of the document. In this circumstance, the overwrite is simply recorded as an edit by the person uploading the document.
By managing fragment IDs externally, developers are delegating responsibility from PageSeeder to themselves. There is some inherent risk in this and it’s not recommended for new developers or those working on their own.