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/nx84dqvsvl?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/c6c6fab10qj?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/f6kzo9yxofu?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/y39i36hg1pg?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/5dhns3deojo?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/md2vo0lkuub?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/umwgtgzylqt?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/65j5ayuvsa6?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/ilk0lnk6fm?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/16ty517go2u?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/0gq6rgxobdc?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/pyob6jiostd?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/c7x78cpa337?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/3zp5fr32sw?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/8r4nq3ch8ul?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/oebtzmt19co?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/mlq9oxdql8j?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/xn217o1aplb?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/g8vtdz1n2j9?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/w7gqbfntqjp?10" /></svg>