Collapse geojson FeatureCollection

temp.py

import json
import sys
import zipfile

output = {
        'type': 'FeatureCollection',
        'properties': {},
        'features': [],
        }

with zipfile.ZipFile(sys.argv[1]) as input_zip:
    for name in input_zip.namelist():
        with input_zip.open(name) as input_geojson:
            data = json.load(input_geojson)
            issues = data['features']
            for issue in issues:
                features = issue['features']
                for feature in features:
                    output['features'].append(feature)

json.dump(output, open(sys.argv[2], 'w'))