When decoding compressed BUFR data, ecCodes does not expand elements whose values are constant across all subsets, i.e. it returns a single value rather than an array of constant values. When this environment variable is set to 1, that behaviour is changed so all values are shown. 

$ export ECCODES_BUFR_MULTI_ELEMENT_CONSTANT_ARRAYS=1

or, within a python program

Toggle constant variable expansion
codes_bufr_multi_element_constant_arrays_off()
codes_bufr_multi_element_constant_arrays_on()

Enabling expansion can increase the output of commands like bufr_dump quite dramatically.

The full list of ecCodes environment variables is here What environment variables are there? - ecCodes FAQ