Subsetting
A typical font may contain hundreds or even thousands of glyphs, often representing characters from many different languages. Oftentimes, users may only need a small subset of the glyphs that are available to them. Subsetting is the process of removing unnecessary glyphs from a font file, usually with the goal of reducing file size. This is particularly important for web fonts, since reducing file size often means reducing page load time. Besides reducing file size, subsetting can also be used for other purposes. For example, Fontslice LLC recently began subsetting fonts as a means of reducing the average transaction cost of font licensing.
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