The license used (CC BY-NC-ND 4.0) is not considered an "Open Source (software) License" by... anyone.
It restricts users' ability to distribute "derivative works", and restricts the type of users that may use it / the way they may use it to noncommercial purposes/contexts. Both of these restrictions are incompatible with any common definitions of Open Source.
It seems you are using the term to indicate "users can see the source code", but that's simply not what "Open Source" means: https://en.wikipedia.org/wiki/The_Open_Source_Definition
The license used (CC BY-NC-ND 4.0) is not considered an "Open Source (software) License" by... anyone.
It restricts users' ability to distribute "derivative works", and restricts the type of users that may use it / the way they may use it to noncommercial purposes/contexts. Both of these restrictions are incompatible with any common definitions of Open Source.
It seems you are using the term to indicate "users can see the source code", but that's simply not what "Open Source" means: https://en.wikipedia.org/wiki/The_Open_Source_Definition