Kovid Goyal, the creator of Calibre says this on the History section of https://calibre-ebook.com/about:

"The name calibre was chosen by my wife, Krittika. The libre in calibre stands for freedom, indicating that calibre is a free and open source product, modifiable by all. Nonetheless, calibre should be pronounced as cali-ber, not ca-libre."

I enjoyed your show, and as it happens, have been using KOReader on my phone for the past few months, where it does a fine job.