To use, select one or more tokens and then right-click on a message in the chat. An option, "Extempore Effect", should appear. Clicking that option will grant a new Effect to all controlled tokens.
The Effect will have its name, description, level, traits, etc. match the message's item ("item" here being a spell, an action, a feat, a weapon, etc.). The duration will usually fit if possible (required some hardcoding and doesn't cover all bases).
The image will fit the item too, but not if it's a "default image" (like the default feat icon or any of the simple 1/2/3-action icons). To avoid having several Effects with the same image (and avoid the boring default images), this module will either use the image of the original item's token/actor, or will randomly pick a simple colored image.
As a bonus feature, right-clicking actual Effect messages will display an "Apply Effect" option to just apply that same effect to the controlled token. This is just a quality-of-life feature.
If you hold the Shift button, the effect's sheet will be opened up for you to see and edit, after being applied.
This is useful if you want to quickly edit the effect - for example:
Rename Mirror Image to "Effect: Mirror Image (3)",
Rename Mummy Rot to "Effect: Mummy Rot (stage 1)"
Change Steal Shadow's duration from Unlimited to 2 hours.
Change Arsenic's image from the picture of a powder to a picture of deadly poison.