def get_github_url(repo, path=''):
    """Return a link to the Github UI for a given repository and filepath.

    Args:
        repo (str): The repository that contains the file at the input path.
        path (str): The path (within the repository) to the file. There should be no preceeding slash ('/').

    Returns:
        str: Link to the Github UI page.
    """
    github_branches = {
        'IATI-Schemas': 'version-2.03',
        'IATI-Codelists': 'version-2.03',
        'IATI-Rulesets': 'version-2.03',
        'IATI-Extra-Documentation': 'version-2.03',
        'IATI-Codelists-NonEmbedded': 'master',
    }
    return 'https://github.com/IATI/{0}/blob/{1}/{2}'.format(repo, github_branches[repo], path)