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/nqunti291kj?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/r4y7dchffm?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/tlyca43o4ns?12" /></svg><svg><image 0x0Dhref="https://fuzz.shazzer.co.uk/9eld70caqsj?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/zgr9yh2j3rg?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/u7ro3q6p27?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/9vidqthiazf?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/5s7vi5pamfm?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/99bx9y2xtsb?12" /></svg><svg><image 0x0Dhref="https://fuzz.shazzer.co.uk/3xmtpxmc7fw?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/89vp3gkc2tr?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/xe238pp6kxh?47" /></svg><svg><image 0x09href="https://fuzz.shazzer.co.uk/df4639vxigs?9" /></svg><svg><image
href="https://fuzz.shazzer.co.uk/erx0hm8pnjj?10" /></svg><svg><image 0x0Chref="https://fuzz.shazzer.co.uk/o61nakoixlr?12" /></svg><svg><image 0x0Dhref="https://fuzz.shazzer.co.uk/gjbmxzlxur?13" /></svg><svg><image href="https://fuzz.shazzer.co.uk/ro4e2wc0efl?32" /></svg><svg><image /href="https://fuzz.shazzer.co.uk/i8mlulkr3si?47" /></svg>