What does magnetic_field mean?

What does tag `world/magnetic_field` mean?

Normally, the magnetic field vector changes with both position and time. What would this single vector represent? Is it something like rough approximation of the field strength at 0,0,0 pose?

I'd suggest either removing this field, or renaming it, because its meaning is quite unclear.

No source file, test, or documentation entry point is named in the issue. Start by locating the definition and documentation for the world/magnetic_field tag, then determine its intended meaning before deciding whether the wording or the field itself should change; done requires an agreed, unambiguous resolution.

Written by the indexing model from the issue text.