The \xhh indicates a hex value of hh. i.e. it is the Python 3 way of encoding 0xhh.

See https://docs.python.org/3/reference/lexical_analysis.html#string-and-bytes-literals

The b at the start of the string is an indication that the variables should be of bytes type rather than str. The above link also covers that. The \n is a newline character.

You can use bytearray to store and access the data. Here's an example using the byte string in your question.

example_bytes = b'\x8a\n\x1e+\x1f\x84V\xf2\xca$\xb1'
encoded_array = bytearray(example_bytes)
print(encoded_array)
>>> bytearray(b'\x8a\n\x1e+\x1f\x84V\xf2\xca$\xb1')
# Print the value of \x8a which is 138 in decimal.
print(encoded_array[0])
>>> 138
# Encode value as Hex.
print(hex(encoded_array[0]))
>>> 0x8a

Hope this helps.

Both repr and str when processing a bytes object will print ASCII characters where possible. Otherwise their hexadecimal values will be shown in the form \xNN.

It might help you to visualise the content if you print it as all hexadecimal as follows:

b = b"H\x00\x84\xffQ\x00\xa6\xff+\x00\x96\xff\xc2\xffI\xff\xa5\xff'\xff\x8a\xff\x19\xff\x19\xff\xf6\xfe\xb0\xfe\xc7\xfeJ\xfel\xfe\xf8\xfd+\xfe\xef\xfd:\xfe\xc3\xfd*\xfe_\xfd\xdf\xfd\n\xfd\xa3\xfd\xc6\xfcq\xfd\xbd\xfc?\xfd"
print(''.join(hex(b_) for b_ in b))

Output:

0x480x00x840xff0x510x00xa60xff0x2b0x00x960xff0xc20xff0x490xff0xa50xff0x270xff0x8a0xff0x190xff0x190xff0xf60xfe0xb00xfe0xc70xfe0x4a0xfe0x6c0xfe0xf80xfd0x2b0xfe0xef0xfd0x3a0xfe0xc30xfd0x2a0xfe0x5f0xfd0xdf0xfd0xa0xfd0xa30xfd0xc60xfc0x710xfd0xbd0xfc0x3f0xfd