Preview ID Title ID Original dimensions
#avatar-buildit-b #avatar-buildit-b__title 16.933px × 16.933px
#avatar-buildit-stacked #avatar-buildit-stacked__title 16.933px × 16.933px
#avatar-impossible-b-fill #avatar-impossible-b-fill__title 64px × 64px
#avatar-impossible-b-outline #avatar-impossible-b-outline__title 64px × 64px

Some SVGs have shapes that can be independently filled via the --grav-co-svg-hl-* custom properties. To visualise this, the above SVGs have such regions coloured in as follows: