<?xml version="1.0" encoding="utf-8"?>
<!--
Fallback Fonts This file specifies the fonts, and the priority order, that will be searched for any
glyphs not handled by the default fonts specified in /system/etc/system_fonts.xml.
Each entry consists of a family tag and a list of files (file names) which support that
family. The fonts for each family are listed in the order of the styles that they
handle (the order is: regular, bold, italic, and bold-italic). The order in which the
families are listed in this file represents the order in which these fallback fonts
will be searched for glyphs that are not supported by the default system fonts (which are
found in /system/etc/system_fonts.xml). Note that there is not nameset for fallback fonts, unlike the fonts specified in
system_fonts.xml. The ability to support specific names in fallback fonts may be supported
in the future. For now, the lack of files entries here is an indicator to the system that
these are fallback fonts, instead of default named system fonts. There is another optional file in /vendor/etc/fallback_fonts.xml. That file can be used to
provide references to other font families that should be used in addition to the default
fallback fonts. That file can also specify the order in which the fallback fonts should be
searched, to ensure that a vendor-provided font will be used before another fallback font
which happens to handle the same glyph. Han languages (Chinese, Japanese, and Korean) share a common range of unicode characters;
their ordering in the fallback or vendor files gives priority to the first in the list.
Language-specific ordering can be configured by adding a BCP 47-style "lang" attribute to
a "file" element; fonts matching the language of text being drawn will be prioritised over
all others.
-->
很明显，这个文件是用来配置字体的。