What do they use it for?
One is one of the largest master distributors of industrial supplies in the world.
Another is a web-based and catalog distributor of consumer goods (mostly apparel.)
Each has acquired 5 competitors in the past 10 years, converting all of them from whatever they were running to their 20+ year old software written in 40+ year old technology. Both were super agile long before any of us ever used the term.
(All client side web software is written in javascript. Some things do change.)
The two companies I cited use InfoBASIC, each on a different variant of the old Pick operating system: