The standard is available at https://www.itu.int/rec/T-REC-X.680/

It's used in many applications such as SNMP, CMIP, LSAP. Ididn't encounter a use case yet.

As stated in the video, the ASN.1 GNU library is under-documented and hard to use without examples. The idea, concept and design is well done though.

(via This is better than protobuf - Tsoding Daily)