Another source code viewer - free and open source. Good for many types;
.pp , .pas, .lpr, .lpk, .lfm, .inc
.pas, .dpr, .dpk, .inc, .dproj, .bdsproj
.c, .cpp,. cc,.h, .hpp,.hh, .cxx, .hxx, . cu
.asm
.e, .ace
.f, .for
.java
.csproj, .xaml, .sln, .vcxproj, .vbproj, .jsproj, .appxmanifest
.bas, .vb
.cbl, .cob
.cs
.css
.htm, .html
.js
.php, .php3, .phtml
.vbs
.bat, .cmd
.dfm, .xfm
.pl, .pm, .cgi
.py
.rb, .rbw
.sh
.sql
.iss
.ini
Sadly doesn't have JSON or YML support yet.