Ilmbase vs. openexr: what are they, what do they do, and what's the difference?

This morning I updated two computers, both running EndeavourOS. I saw an option to replace ilmbase with extra/openexr and, as the default was Y, I selected it and allowed the update to proceed, which it did normally.

My question is in the title of this post: what it ilmbase vs. openexr? Does one have an advantage over the other? And what would have happened had I NOT selected to remove ilmbase and replace it with openexr?

Thanks for any information.

Lawrence

https://www.archlinux.org/packages/extra/x86_64/openexr/
https://www.openexr.com/
https://yum-info.contradodigital.com/view-package/base/ilmbase/

In addition to these three links, when pacman throws you And it is because that way he eliminates that library and looks for a replacement for it. The developers do it that way. if you face pacman putting N instead of Y the update is not carried out, most of the time.
The rest is explained by the links, to read.
https://bbs.archlinux.org/viewtopic.php?id=250160