Six properties had words, and thirty-seven did not
Position, size, angle, opacity, colour and text had sentences of their own on the timeline. The other thirty-seven animatable properties in the editor read as one word: Changes.
One word for thirty-seven different things
A shadow fading, corners rounding off, a border thickening, and thirty separate 3D properties all said the same thing, and the collapsed row that merges a layer's lines into one said it too.
It lands hardest exactly where it can least afford to. In the simple timeline the word is all there is: somebody who never opens a property row has nothing else to read, and a row that says Changes tells them their animation contains something.
The words were already written down
Every animatable property already carried a name and a verb, written for the keyframe cards: shadow strength fades, a corner rounds off, a border thickens. The sentence existed and the timeline was not reading it.
There is one table now, and both read from it. A property added to that table later is named on the timeline without anybody coming back to a second list — and a property added without a verb cannot quietly fall back to a shrug, because there is no fallback left.
A few of the verbs are better for being read twice. A corner rounds off rather than increasing.
Holding still is a sentence too
Two keyframes holding the same value is a real thing to do — it is how you make something wait before it moves — and it was being described as a change, which is the opposite of what it is.
A stretch whose ends are the same now says so in the property's own name: holds shadow strength, holds position.
Three separate hand-written lists used to decide whether a label meant nothing is happening here, and one of them had already lost one of the labels it needed. They are one rule now, written next to the words it judges, because a hold written from a property's own name has no fixed spelling to keep a list of.
And the simple mode can ask for what it can read
The list of things that can happen to a layer is generated from what the layer is wearing rather than hand-written. A layer with a shadow is offered a shadow that fades away, in the same list as a fade in and a slide, and the row afterwards says the same sentence — because the offer and the description come from the same place.
Only the directions with an end that needs no inventing: away to nothing, and in from nothing. Anything else is a number somebody would have to be asked for, and a one-press step that stops to ask is not a one-press step.