Playing on N3.1.3
Building the Thunderbird causes a crash due to the fixed Megachaingun being improperly defined in Piratez.rul. It's defined as "fixedWeapons: [STR_UAC_MEGACHAINGUN]" when it should be "fixedWeapons: [STR_UAC_MEGACHAINGUN_UC]".
The Thunderbird also seems to have a resource file improperly assigned in Piratez_Resources.rul. "- type: INTICON.PCK" has "Resources/Planes/Thunderbird_Dogfight.gif" assigned for both 232 and 243, which results in the minimised dogfight icon looking weird (no background). I think 232 should be "Resources/Planes/Thunderbird_Minimised.gif" instead, that gets it looking correct for me at least.
It does not appear possible to unlock the researches "STR_TRADERS_COM_KNOWHOW" (GUILDMASTER'S SECRETS), "STR_ACADEMY_COM_KNOWHOW" (ACADEMY PROVOST'S SECRETS) and "STR_MUTANT_ALLIANCE_LORE" in the game due to bugs in Piratez.rul. The Mutant Alliance Lore has needItem set to True which seems to prevent it from unlocking.
Much belated edit (28/01/23):
Realised I should put the instructions on how to fix the Provost and Guildmaster bugs here so people can find it more easily.
Spoiler:
If you are deep enough into the lategame for VIP interrogations and don't want to wait for a patch, here's how to fix it.
Get your favorite text editor and open up (starting from your OpenXCOM folder) user\mods\Piratez\Ruleset\Piratez.rul
To fix the academy provost, look for an entry that looks like this:
- name: STR_SECTOID_COMMANDER
cost: 35
points: 100
needItem: true
destroyItem: true
To the getOneFreeProtected section, add the following lines:
STR_INTERROGATION:
- STR_ACADEMY_COM_KNOWHOW
For the guldmaster:
Look for this:
- name: STR_GUILD_COMMANDER
cost: 35
points: 100
needItem: true
destroyItem: true
This one doesn't have a getOneFreeProtected section, so you need to add one yourself. Just below
getOneFree:
- STR_FISTY
Add this:
getOneFreeProtected:
STR_INTERROGATION:
- STR_TRADERS_COM_KNOWHOW
Careful with editing that file, make a backup first, don't use any tab-indentations, only spaces. If you tamper with it improperly, OpenXCOM will give you an error message if you start it.
And in case you're wondering why the academy provost is called Sectoid Commander in code, let's just say this mod used to be a palette swap that just replaced X-Com weapons with pirate-y counterparts. It's come a long way since, but some of internal references still call academicians sectoids, traders floaters and church snakemen.