What do //\"/ at the end of a bash variable mean?

Question

bash

The script receives a parameter of this format:
"${1//\"/}"

Answer 1

It's called bash parameter substitution
https://www.tldp.org/LDP/abs/html/parameter-substi...
Your example is described as
${var//Pattern/Replacement}
Global replacement. All matches of Pattern, within var replaced with Replacement.
Usage example - strips double quotes from input
bash-3.2$ ./test1.sh 'aaa""bbb'
aaabbb
bash-3.2$ cat test1.sh
#!/bin/bash
testvar=${1//\"/}
echo $testvar

Answer 2

Replacing the substring
${string/substring/replacement} The
details are well described here.