Constant ttf_parser::tables::gvar::PHANTOM_POINTS_LEN

const PHANTOM_POINTS_LEN: usize = 4;

’The TrueType rasterizer dynamically generates ‘phantom’ points for each glyph that represent horizontal and vertical advance widths and side bearings, and the variation data within the gvar table includes data for these phantom points.’

We don’t actually use them, but they are required during deltas parsing.