I was just looking at this notebook
and discovered that if I remove the import { vl } from "@vega/vega-lite-api" so the notebook uses vl library in observable, I get different size charts.
With import { vl } from "@vega/vega-lite-api"
Without import { vl } from "@vega/vega-lite-api"
The imported vl is a wrapper that sets some default options: Vega-Lite API v4 / Vega / Observable
Observable’s vl (part of the stdlib) on the other hand is the “vanilla” library without any changes: stdlib/dependencies.js at d0d4736bd206441aa3f54009760aab6297258c66 · observablehq/stdlib · GitHub
