The image is an automated build without any dependency from the source repository other than the Dockerfile (which is published for your review).
aria2c is compiled statically, so the executable can be used in any other linux image. I recommend a multi-stage build to accomplish this. An example Dockerfile is given below:
FROM tbaxx/aria2:1.33.1 as builder FROM debian:buster-slim COPY --from=builder /usr/local/bin/aria2c /usr/local/bin/aria2c EXPOSE 6800 ENTRYPOINT ["aria2c"]