Personally, I think it's a little unfair to expect the core Abantecart developers to develop every little thing for every little country or situation. At the end of the day, people who use this are using FREE, open source software. Either learn to code or pay someone a high enough amount to develop a custom extension for your situation. If no one wants to do it, either you're paying too low or it's not possible.
I really would NOT want the developers to work on items which benefit a few custom installs since it takes away time from something else and as someone with kids, job, working with this as well, time is always limited.
I believe a lot or all of the Devs also have full time jobs as well so I'm guessing a lot just do this on the side as well.
On the Guatemala Quetzal, there are about 16 million people in TOTAL in ALL of Guatemala. There is over 29 million in Texas alone (1 US state). Like with Apps on Android or IOS, don't waste time on 1 off solutions which benefit a small population. Your time is valuable and I hope that the core developer's time is spent on things which benefit the whole userbase of Abantecart.