Keiraville and BNAndras,
So, it sounds that things are up to the track maintainer. And I have just noticed that the github repository of the scheme track is tagged “unmaintained” and “community-contributions-paused”. Does this really mean that the scheme track has no maintainer?
Borderite
P.S. list-ops is not difficult to solve in the Lisp family of languages including scheme.
Correct. There is no scheme maintainer. There are members of the community that have the ability to approve PRs across unmaintained and/or all Exercism repos, though. Those tend to be rather passive/reactive, though, opposed to active maintenance.
Lacking a dedicated maintainer, that choice tends to land with whomever can make a compelling argument and convince the more senior Exercism maintainers 
Oops, I missed that when I made that issue. I had checked on the Exercism website whether List Ops was available, but it wasn’t there. I assumed it meant List Ops hadn’t been implemented, but it had been.
List Ops is marked as deprecated, and I’m not sure why. I couldn’t find a related GH PR. The exercise was added in 2015 before canonical test cases were available in 2017. So if we deprecate Accumulate and turn List Ops back on, we should sync that test suite sooner or later.
However, since it’s not in the input/exercises folder, the CI currently isn’t testing that exercise either. So unless we just completely overhaul the CI, either Accumulate or List Ops should be added to input/exercises. I wouldn’t bother adding the one that’ll be deprecated going forward.
Thanks for your patience. There’s a lot going on with this repository that I’m not accustomed to with my own tracks. This track had a long-term maintainer, but they’ve been inactive for a while so this is a bit of an adventure for us too.
Thanks for your detailed explanation. I have just finished all practices in Scheme. 
Please let me know if I can be any help.
I have just found a way to pass all tests in the “accumulator” exercise in the Scheme track. If you put
(print-set! r7rs-symbols 'r7rs-symbols)
on the second line of the solution, the problem we have been discussing can be avoided. This command forces guile to use the |…| expressions for “weird” symbols like “1+” instead of #{…}# expressions, which chez does not understand.
I also found that guile on my machine automatically uses the |…| expressions even without the above-mentioned command. The difference between my machine and the docker image of the Scheme track is the version of guile; mine is 3.0.8 while the docker image’s is 2.2-dev. It is probably the time to upgrade guile in the docker image.