$ fq -i -d mp3 . test.mp3
mp3> .headers[0].header.magic | ., tovalue, toactual, tosym, type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|49 44 33                                       |ID3             |.headers[0].header.magic: "ID3" (valid)
"ID3"
"ID3"
null
"string"
3
mp3> .headers[0].header.magic[0] | ., type, length?
"I"
"string"
1
mp3> .headers[0].header.magic[-1000] | ., type, length?
""
"string"
0
mp3> .headers[0].header.magic[1000] | ., type, length?
""
"string"
0
mp3> .headers[0].header.magic[1:3] | ., type, length?
"D3"
"string"
2
mp3> .headers[0].header.magic[0:-1] | ., type, length?
"ID"
"string"
2
mp3> .headers[0].header.magic[-1000:2000] | ., type, length?
"ID3"
"string"
3
mp3> .headers[0].header.magic["test"] | ., type, length?
null
"null"
0
mp3> [.headers[0].header.magic[]] | type, length?
error: cannot iterate over: string
mp3> .headers[0].header.magic | keys
error: keys cannot be applied to: string
mp3> .headers[0].header.magic | has("a")
error: has cannot be applied to: string
mp3> .headers[0].header.magic | has(0)
error: has cannot be applied to: string
mp3> .headers[0].header.magic | type
"string"
mp3> .headers[0].header.magic | tonumber
error: invalid number: "ID3"
mp3> .headers[0].header.magic | tostring
"ID3"
mp3> .headers[0].header.magic + ""
"ID3"
mp3> .headers[0].header.magic + 1
error: cannot add: string ("ID3") and number (1)
mp3> .headers[0].header.magic._start | ., type, length?
0
"number"
0
mp3> .headers[0].header.magic._stop | ., type, length?
24
"number"
24
mp3> .headers[0].header.magic._len | ., type, length?
24
"number"
24
mp3> .headers[0].header.magic._name | ., type, length?
"magic"
"string"
5
mp3> .headers[0].header.magic._actual | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|49 44 33                                       |ID3             |.headers[0].header.magic: "ID3" (valid)
"string"
3
mp3> .headers[0].header.magic._sym | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|49 44 33                                       |ID3             |.headers[0].header.magic: "ID3" (valid)
"null"
0
mp3> .headers[0].header.magic._description | ., type, length?
"valid"
"string"
5
mp3> .headers[0].header.magic._path | ., type, length?
[
  "headers",
  0,
  "header",
  "magic"
]
"array"
4
mp3> .headers[0].header.magic._bits | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|49 44 33                                       |ID3             |.: raw bits 0x0-0x3 (3)
"string"
24
mp3> .headers[0].header.magic._bytes | ., type, length?
   |00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f|0123456789abcdef|
0x0|49 44 33                                       |ID3             |.: raw bits 0x0-0x3 (3)
"string"
3
mp3> .headers[0].header.magic._error | ., type, length?
null
"null"
0
mp3> .headers[0].header.magic._gap | ., type, length?
false
"boolean"
mp3> .headers[0].header.magic.a = 1
error: setpath(["headers",0,"header","ma ...]; 1) cannot be applied to {"footers":[],"frames":[{" ...: expected an object but got: string ("ID3")
mp3> .headers[0].header.magic[0] = 1
error: setpath(["headers",0,"header","ma ...]; 1) cannot be applied to {"footers":[],"frames":[{" ...: expected an array but got: string ("ID3")
mp3> .headers[0].header.magic.a |= empty
error: delpaths([["headers",0,"header","m ...]) cannot be applied to {"footers":[],"frames":[{" ...: expected an object but got: string ("ID3")
mp3> .headers[0].header.magic[0] |= empty
error: delpaths([["headers",0,"header","m ...]) cannot be applied to {"footers":[],"frames":[{" ...: expected an array but got: string ("ID3")
mp3> .headers[0].header.magic | setpath(["a"]; 1)
error: setpath(["a"]; 1) cannot be applied to "ID3": expected an object but got: string ("ID3")
mp3> .headers[0].header.magic | setpath([0]; 1)
error: setpath([0]; 1) cannot be applied to "ID3": expected an array but got: string ("ID3")
mp3> .headers[0].header.magic | delpaths([["a"]])
error: delpaths([["a"]]) cannot be applied to "ID3": expected an object but got: string ("ID3")
mp3> .headers[0].header.magic | delpaths([[0]])
error: delpaths([[0]]) cannot be applied to "ID3": expected an array but got: string ("ID3")
mp3> ^D