Scattergl renderer default transition uncertainty after plotly chart_studio split

Plotly's core rendering pipeline does not prescribe an automatic transition from SVG-based Scatter to WebGL-accelerated Scattergl for traces exceeding a point count threshold, leaving the cutoff entirely user‑specified. This design choice creates ambiguity when scaling large scatter plots, particularly across environments where renderer defaults differ between classic Notebook, JupyterLab, and VS Code. The separation of Chart Studio publishing into the chart_studio package further isolates core rendering decisions from online workflow concerns, but does not resolve the offline trace‑type selection problem.

What criteria determine the Scatter-to-Scattergl transition for a trace of N points? Does any plotly version provide a configurable default renderer selection beyond explicit trace type assignment? How does the renderer default interact with the chart_studio publishing pipeline when large traces are exported?