Where are information about syntax highlighting xml files?

I am interested in syntax-highlighting framework. I am writing own Qt widget for viewing files and I want enable syntax highlighting and maybe folding. In data/syntax is many xml files. Where I can get info about how to use it? Also I can use this information not directly from xml, but by using libkf5syntaxhighlighting-dev in Ubuntu. How can I use it?
QPlainTextEdit can use

KSyntaxHighlighting::Repository repository;
KSyntaxHighlighting::SyntaxHighlighter *highlighter;

there is


Is possible use KSyntaxHighlighting with own component?

I found

I have repository and definition

KSyntaxHighlighting::Repository repository;
const KSyntaxHighlighting::Definition definition = repository.definitionForFileName("a.c");

Definition has multiLineCommentMarker() and keywordLists()
has also Format

KSyntaxHighlighting::Format format =  definition.formats()[5];

but format has no rules, only text attributes
Where are rules, for example: how detect int, identifier or haxadecimal,octal? (without KSyntaxHighlighting::SyntaxHighlighter and QTextDocument)