he doesn't extract or mount them, he's trying to say in the OTA updater zip you can easily see which partition is which from the updater-script and by looking through the files in the zip.
For example:
[HIGH]ui_print("Patching adsp image...");
apply_patch("EMMC:/dev/block/mmcblk0p8:5617480:f09ea472961147424d430e97efd35f5dab08a5c3:5601608:4c02b3c5d7db624f3112ab6cebbeba7c64678a75",
"-", 4c02b3c5d7db624f3112ab6cebbeba7c64678a75, 5601608,
f09ea472961147424d430e97efd35f5dab08a5c3, package_extract_file("patch/adsp.mbn.p"));[/HIGH]from the script you can see that adsp is partition number 8 aka mmcblk0p8. See what he's saying? i thought you knew that while trying to get the jb partitions the other day lol. Anyway yeah thats how most devs finds out what partition is what/does what, through Official OTA updater-scripts. Which is why i kind of hesitate to flash other phones partitions other than my own cause even though we have the name for them in the zip, we dont know what the hell they do lol I remembered an old friend and amazing dev interdpht was working on getting new update rooted on to everyones Transform UItra, he ended up flashing some else IMED partition which automatically gave him the other persons IMEd number haha. In the end he never backed it up which caused him to buy a new ultra