What is this "Xliff Alternate" TM that keeps appearing?

[EileenP]

When I change a translation, the original translation is often left in a TM called "Xliff Alternate". (I can see this in the lower pane.) And sometimes not.

Why the difference?

What is the function of this TM?

Why can I not find any info about this in the online help? (Rhetorical question, sorry.)

Thanks!

[rob hollinger]

This happens after updating a project. If any of the segments were already translated and those segments were updated, you will see this in the TM Suggestions pane.
The target translations are kept even after updating a project. These translations are then used as suggestions.