Reasoning why this is part of the core and not a separate addon:
The impact of this function is extremely lightweight when (almost) no
aliases are defined so someone who isn't using this should not have a
worse experience.
Additionally including it in the core (similarly to the discounts,
taxes and restrictions) promotes it's availability while not massively
increasing the maintainability.
As for the OddItem removal:
That plugin hasn't been developed for over 7 years and such unique
plugin support should really be added via separate addon using the
events system which, with the new ItemStringQueryEvent, now actually
supports doing that from an external plugin.
If someone really managed to run their own private fork of OddItem for
all those years then they should be able to also provide such a simple
addon.
Also add tax bypass permissions (#204, ChestShop.notax.buy/sell). When buying with that permission the buyer does not have to pay the tax (the seller will still get the reduced amount), when selling the seller will get the full amount instead of one lowered by the tax.
The permissions of the shop owner play no role due to there not being a good way of checking offline player permissions and it being a bit non-obvious for the buying/selling player if a shop would be with or without tax. This way all that gets changed is the amount the player pays/receives and not the shop owner (and the player should know their permissions/rank already)
The transfer event was necessary in order to correctly resolve who triggered the transaction. Economy adapters are now required to implement a listener for each of the events. It's also recommended that economy adapters that support transfers directly use that instead of passing it through subtract and add with the processTransfer method.
Iirc this was only async for database logging or name resolving. Neither of these is done anymore and async access of the Bukkit API can lead to strange problems like the CME described in the mentioned issue.
This changes events to store the database Account instead of an OfflinePlayer and deprecates any event method that uses/returns OfflinePlayer. This is necessary as Bukkit#getOfflinePlayer(String) queries Mojang for the UUID when the user was not found in the local cache. As we already store this information (name to UUID mapping) in our database we should not have no need to rely on querying Mojang. (This might make transactions fail for shop owners that haven't played before but that shouldn't really be an issue in most cases)