Great news! The online index and reviewing service, ZbMath, is to become open access from the start of 2021. This will be of great benefit to mathematicians in developing countries.
If, in the meantime, mathematicians from developing countries would like to access ZbMath, then this is possible. Details of how to make this happen are given on the EMS-CDC webpage here.
More information on the move to open access is available here.