I would like to add a new value to a custom field Select List. There is no ADD operation for this custom field, only GET.

Its a shame because you provide a feature for adding VERSIONs to the version list, which appears to be a similar operation.

For the operation to be possible, you would need to know the project or possibly the context that the custom field belongs to? I guess the context, as a context can apply to one or more projects.

Just to be clear, this is not an issue edit operation, this is on the custom field and the context it belongs to.

It would be a worthy addition because we all use continuous integration nowadays be it jenkins or in our case, in house. These all churn out build IDs and versions at a prodigious rate which the Test and QA teams like to have in their drop down lists.