Shumlib is the collective name for a set of libraries which are used by the UM; the UK Met Office's Unified Model, that may be of use to external tools or applications where identical functionality is desired. The hope of the project is to enable developers to quickly and easily access parts of the UM code that are commonly duplicated elsewhere, at the same time benefiting from any improvements or optimisations that might be made in support of the UM itself.
Note that this Git repository is provided purely as a means to allow public access to Shumlib, rather than as a base for development - the actual development of Shumlib takes place on the Met Office's Science Repository Service at https://code.metoffice.gov.uk/ (this is a restricted site with controlled access for UM partners). As a result one should not expect to see pull-requests etc. actioned directly (issues and feedback are still welcomed but will be migrated to tickets within the SRS for development).
Although the UM has a restricted commercial licence, code that is moved into Shumlib has been assessed and re-classified under the more permissive BSD 3-Clause licence. The aim of this is to allow maximum flexibility and as few barriers to usage as possible. However we would still encourage the feedback of modifications and developments (particularly bugfixes) rather than modified redistribution.
The documentation resides in the doc directory.