A font subset that halved the largest contentful paint

A variable font covering Latin, Cyrillic and Greek, on a site that renders English and Turkish.

$ pyftsubset Inter.ttf 
    --unicodes='U+0000-00FF,U+0100-017F,U+2000-206F' 
    --layout-features='kern,liga' 
    --flavor=woff2 --output-file=inter-subset.woff2

  before  412 KB
  after    88 KB

# and the CSS that stops it blocking
@font-face { font-display: swap; }

Subsetting is the largest single win available on a page whose largest element is text, and it is a build step nobody adds because the font arrives as a file that works. The Turkish range needed the Latin Extended-A block, which is the sort of thing that is invisible until somebody’s name renders with a fallback glyph — checking the actual content rather than assuming a script is the part to be careful about.