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/i8yipkih2t8?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/zx7lrixlx3k?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/i5p14hnhfve?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/wxcsdsp3qj?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/n8e24x9hg5?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/rf0anctyvdc?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/n33o757ff7?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/rdsiosse36?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/cwnlg4l1f2d?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/391dl7wjspx?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/e51npvcrax?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/1zx2tnvyuzw?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/3b7t5s5i5fg?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/2m6j2qw50ep?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/9nm9z4fept?12" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/nx0s6da6w2o?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/i3d201o2z?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/ln5uv47fbm?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/6s8rnell4bg?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/5bnhgb84ggo?10" /></svg>