This page contains some 1.5.0 related datamining updates (mostly from the executable itself).
Diff from 1.4.0: https://pastebin.com/9FEx6Wjr
If the villager is making a Halloween DIY that you have already learned, there is a 70% chance of receiving 5x orange pumpkins, and 30% chance of receiving 1x candy. You will not get the DIY card again.
The reward is determined when you first talk to the villager.
Internally, pumpkins are referred to as both Squash and Pumpkin.
The FreeParam flags for pumpkin plants are as follows:
  [0000000H] [XXXYYYYY] H = hydration flag (HF), 0 or 1 X = growth counter (GC), 3 bits but capped at 2 Y = watering counter (WC), 5 bits but capped at 20
Pumpkins share a few similarities with flowers, notably:
There is also code to reset the watering counter when the pumpkin is dug up, but is currently not used.
When a fully grown pumpkin plant (stage 3) is picked, pumpkins of the same color as the plant are obtained. The number of pumpkins is equal to the growth counter plus one.
GrowUp, if the pumpkin plant is not yet fully grown, and it is not on the beach,
If the pumpkin plant is fully grown, its flags are unchanged during
Planting pumpkin starts bought from Nook’s Cranny or Leif results in a PltVgtSquash0. These grow up each day into PltVgtSquash1, and then PltVgtSquash2.
PltVgtSquash2 has a 70% chance of growing up into a PltVgtSquash3Orange, and a 10% chance each of growing up into PltVgtSquash3Yellow, PltVgtSquash3Green, or PltVgtSquash3White.
Planting a [Color] pumpkin will result in PltVgtSquash0[Color]. These grow up each day into PltVgtSquash1[Color], PltVgtSquash2[Color], and then back into PltVgtSquash3[Color].
Picking a PltVgtSquash3[Color] pumpkin plant will revert it into a PltVgtSquash1[Color] plant.
GrowUp, pumpkins are processed after bushes and before weeds.
Pumpkin planting and growth do not care about the date; they grow year-round.
There are no changes to the return gift logic in the game executable, and only minor changes in EventFlow (special dialogue for gifting a pumpkin, but it’s still treated as an edible gift like fruits – a 1 friendship point gift).
1.5.0 added code for handling
EventFlowActionDecideEventReward('cHalloweenReward'), which does not appear to be used in the EventFlow files at the moment.
pool = empty item pool if cPlayer:GetHalloweenRag not set -> add 0x1d79 (RugSquareHalloweenL00) to pool if cPlayer:GetHalloweenWallPaper not set -> add 0x33a8 (RoomTexWallHalloween00) to pool if cPlayer:GetHalloweenFloor not set -> add 0x33a9 (RoomTexFloorHalloween00) to pool if cPlayer:GetHalloweenStickRecipe not set -> add 0x33b5 (ToolStickHalloween) to pool if cPlayer:GetHalloweenGarland not set -> add 0x33a6 (FtrHwnDecorationWall) to pool if cPlayer:GetHalloweenTableSetting not set -> add 0x33a7 (FtrHwnTablesetting) to pool if cPlayer:GetHalloweenBag not set -> add 0x32d7 (BagBackpackHalloween0) to pool if pool is empty: - 7% 0x33a6 (FtrHwnDecorationWall) - 6% 0x33a7 (FtrHwnTablesetting) - 11% 0x11af (SquashGreen) x4 - 10% 0x11ae (SquashYellow) x4 - 10% 0x11b0 (SquashWhite) x4 - 56% 0x11ad (SquashOrange) x4 otherwise: - pick item without catalogue constraint - do some special handling for 0x33b5 (ToolStickHalloween)