D.16 Thread List Format
To efficiently update the list of threads and their attributes, gdb issues the qXfer:threads:read packet (see qXfer threads read) and obtains the XML document with the following structure:
<?xml version="1.0"?> <threads> <thread id="id" core="0"> ... description ... </thread> </threads>
Each thread element must have the id attribute that identifies the thread (see thread-id syntax). The core attribute, if present, specifies which processor core the thread was last executing on. The content of the of thread element is interpreted as human-readable auxilliary information.