Partially reads blueprint-storage.dat, the file appear to be completely auto generated and its a chore to reverse engineer

blueprint-storage.py

#!/usr/bin/env python3

from pprint import pprint
from construct import *

class VersionStringAdapter(Adapter):
    def _decode(self, obj, context, path):
        return ".".join(map(str, obj))

Version = VersionStringAdapter(Int16ul[4])

# kind -> id
# 0 -> 0 is blank for icons

ModList = PrefixedArray(Int8ul, PascalString(Byte, "ascii") >> PascalString(Byte, "ascii"))

ent_names = Struct(
	"prototype" / PascalString(Byte, "ascii"),
	"count" / IfThenElse(this.prototype == "tile", Int8ul, Int16ul),
	"entity" / (IfThenElse(this._.prototype == "tile", Int8ul, Int16ul) >> PascalString(Byte, "ascii"))[this.count],
)


dat = Struct(
	"Version" / Version,
	"u1" / Byte,
	"modlist" / ModList,
	"u3" / PrefixedArray(Int16ul, ent_names),
	"u4" / Int16ul,
	"seqno" / Int32ul,
	"mtime" / Int32ul,
	"x" / Bytes(6),
	"bp_book" / Struct(
		"kind" / Byte, # blueprint = 0, book = 1, decon = 2, upgrade = 3
		"seqno" / Int32ul, # sequence number
		"item_id" / Int16ul, # item? blueprint book = 71
		"title" / PascalString(Byte, "utf-8"),
		# end of common header?
		"u1" / Bytes(7),
		"Version" / Version,
		"unk1" / Byte,
		"modlist" / ModList,
		# Here be dragons
		"description" / PascalString(Byte, "utf-8"),
		#"icons" / PrefixedArray(Byte, Byte >> Int16ul),
		"unk2" / Int8ul,
		"ent_count" / Int32ul,
		"ents" / Struct(
			"entity" / Int16ul,
			"pos" / Int8sl[2][2],
			"u1" / Byte,
			"u2" / Byte,
			"direction" / Byte,
			"unk" / Bytes(6),
		)[this.ent_count]
	)
)

with open("blueprint-storage.dat", "rb") as fd:
	print(dat.parse_stream(fd))