Command line argument to "find" and "grep" data inside "xattr -l" atrributes?
If you could be sure the file were JSON format, there might be a better way to do this, but you'd probably need to know something of the structure of the JSON records.
However, if I understand your question correctly, I think you can get what you want with grep if you use the -o or --only-matching option (see man grep for details)
# create a string 'STRINGX' to test a regex
% STRINGX='net.filebot.metadata: {&quot;@type&quot;:&quot;Movie&quot;,&quot;year&quot;:1983,&quot;imdbId&quot;:85478,&quot;tmdbId&quot;:38291,&quot;language&quot;:&quot;en&quot;,&quot;id&quot;:38291,&quot;name&quot;:&quot;Educating Rita&quot;,&quot;aliasNames&quot;:[]}'

# try a regex that includes '&quot;@type&quot;: plus an alphanumeric string that follows
% echo $STRINGX | grep -o '\&quot;@type\&quot;:\&quot;[a-zA-Z0-9]*\&quot;'

# which yields this as output:
&quot;@type&quot;:&quot;Movie&quot;

# to print only the value of @type, one option is to use sed:
% echo $STRINGX | grep -o '\&quot;@type\&quot;:\&quot;[a-zA-Z0-9]*\&quot;' | sed 's/^.\{8\}//' 
&quot;Movie&quot; 

So - pipe your xattr -l output to the grep command as shown above.
You may be able to do a better job on the regex as I don't know if there are any rules that define characteristics such as maximum length, or presence of special characters, etc.
Let us know how this works, or if you have questions &amp; we'll try to answer.