IRD-dev on "[Plugin: Search & Replace] How to use to CHANGE DOMAIN name only"

So far, I have not executed! I am grateful that you're responsive on this weekend evening (2330 CEST)

A few points for you:
(1) After doing a backup, the button to download failed to do anything .. but disappeared after clicking. Where is the backup physically stored on the server? I'll fetch it via FileZilla.

(2) The Search & Replace (dry run) located MANY instances. The report ran off the lower part of my Chrome browser and, despite the vertical scrollbar, it was still impossible to see the last few lines. Moreover, attempting to select-all unfortunately also included data from behind the non-modal pop-up. I merely wanted to keep a copy handy, for my own review.

Aside from that, it looks like it's finding accurate data. My only remaining conce is that I noticed in the DRY RUN results the following changed values (other than my replacement text):

row 457 column option_value Old value: a:1:{i:0;a:1:{i:0;s:35:"mydomain.com.temp.work.com/";}} New value: a:1:{i:0;a:1:{i:0;s:18:"mydomain.com/";}}

What is the value "S" and why would it change?

Vielen Dank, wieder, für Ihre freundliche Unterstützung!