Delta applies syntax-highlighting and other enhancements to standard grep output such as from ripgrep (aka rg), git grep, grep, etc. If you don't need special features of git grep, then for best results pipe rg --json output to delta: this avoids parsing ambiguities that are inevitable with the output of git grep and grep. To customize the colors and syntax highlighting, see grep-match-line-style, grep-match-word-style, grep-context-line-style, grep-file-style, grep-line-number-style. Note that git grep can display the "function context" for matches and that delta handles this output specially: see the -p and -W options of git grep.