There are a bunch of slot suggestions starting with weapon.* that aren't meaningful, and which aren't documented in the 24w10 article. For example weapon.*0 corresponds with weapon.mainhand and weapon.*3 corresponds with armor.legs.
How to reproduce:
Type the following command in chat, and notice the suggestions
/execute if items entity @s weapon.*/execute if items entity @s weapon.*Run the following command, and notice that the item is placed in your legs slot
/item replace entity @s weapon.*3 with minecraft:chainmail_leggings/item replace entity @s weapon.*3 with minecraft:chainmail_leggings
Are you referring to the sequence of suggestions? It's organized alphabetically, meaning that numbers may not follow the order you'd expect when counting. By sorting alphabetically, I'm referring to arranging items based on ASCII codes, which include non-letter characters like numbers. This leads to sequences such as 1, 10, 11, 12, 13, 14... 19, 2, 20. This arrangement is likely intentional.
Edit: Thank you for providing clarification in the description. The problem I'm discussing is being monitored under the reference MC-269157 and is not planned to be fixed.