This R chunk uses #| fig-align: center and does produce HTML with that tag:
<img src="index.markdown_strict_files/figure-markdown_strict/quantile-tune-res-1.png" data-fig-align="center" width="480" />
However, on local render, it does not appear to be aligned. Inspect Elements from the browser did not show me anything conclusive. @cwickham

This R chunk uses
#| fig-align: centerand does produce HTML with that tag:However, on local render, it does not appear to be aligned. Inspect Elements from the browser did not show me anything conclusive. @cwickham