Uses CSP violations to determine if external resources have been requested. This fuzzes characters before the href attribute in SVG.
<svg><image $[chr]href="https://fuzz.shazzer.co.uk/$[rand]?$[i]" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/ic6o4lhlcps?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/2cxu2o10u3u?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/tt5fwmwp8ph?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/5384lug8ad8?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/r6zh94qzfe?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/he6pfs6k11a?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/s6c0yxo2hbk?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/no5iu6qr5jm?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/cbeozhiyoza?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/3vi1w3ihyzu?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/xrw921b4x7?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/dsjtj2f7sc9?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/r68z76vvsvo?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/3oamxa9yo4j?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/d7703zco75a?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/8iwo40w017p?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/tc7q1cwz8sc?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/qr8buhsuw6c?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/nsbkgr0a36?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/qcnt7wryl99?10" /></svg>