Extra GtkSourceView language definitions
A *.lang file is needed by GtkSourceView to support syntax highlighting for a certain language.
Sources of *.lang files:
- Look first at the upstream *.lang files shipped by GtkSourceView. 
- This wiki page.
- GNOME's current issue tracker: https://gitlab.gnome.org/GNOME/gtksourceview/issues?label_name%5B%5D=0.+New+%2A.lang+file for new language definitions. 
- GNOME's current issue tracker: https://gitlab.gnome.org/GNOME/gtksourceview/issues?label_name%5B%5D=0.%20Existing%20*.lang%20file for existing language definitions. 
- GNOME's deprecated issue tracker: https://bugzilla.gnome.org/browse.cgi?product=gtksourceview under "New *.lang file" 
See the reference documentation to know how to write a language definition file.
List
- apache.lang: Apache configuration files, see also this bug report. 
- apdl.lang: ANSYS APDL files. 
- ascend.lang: ASCEND modelling environment. 
- asm-intel.lang: Intel & AMD assembly, x86 & x86-64, Intel syntax. 
- axe.lang: Axe Parser, a programming language for TI-83/TI-84 calculators. 
- bioSyntax: Computational biology formats collection. SAM, VCF, PDB, FASTA (NT+AA), FASTQ, GTF + more. (lang files) 
- cfengine2.lang: cfengine2 receipe files. 
- cython.lang: Python extended with Cython-specific keywords and constants 
- edifact.lang: UN/EDIFACT message definition. 
- fasta.lang: FASTA biological sequence definition (DNA sequences only). 
- gnuplot.lang: gnuplot graphing utility 
- i386asm.lang: i386 AT&T syntax assembly language. 
- imacros.lang: iMacros browser-based macro recorder 
- kv.lang: Kivy's user interface design language 
- latex.lang: alternative language file to replace the current one included by default; a more complete definition of LaTeX. 
- logtalk.lang: Logtalk programming language. 
- lout.lang: Lout document formatting system. 
- maude.lang: Maude syntax highlighting. 
- mustache.lang: Syntax highlighting for Mustache (see bug 741626). 
- msc.lang: Syntax highlighting for mscgen (Message Sequence Charts generator) 
- nasal.lang: Nasal, the FlightGear flight simulator scripting language. 
- nix.lang: Nix language, the purely functional language manager. 
- Pig Latin: For writing programs using Apache Pig for the Hadoop platform. Pig 0.12 support is included in GtkSourceView 3.16; use this link for older or newer versions of Pig. 
- Ruby: Ruby and Ruby templating (erubis, tenjin...) hacks. 
- rvt.lang: Rivet, Tcl for web server side scripting. Language file from the Tcl language file to highlight the markups "<?" and "?>". 
- shader.lang: id Tech 3 shader scripts. 
- tradacom.lang: Tradacom message definition. 
- wml.lang: Wesnoth Markup Language. 
- x12.lang: ANSI ASC X12 message definition. 
- xkb.lang: xkb X11 keyboard definition files. 
- xorg.conf.lang: xorg.conf files. 
- dts.lang: Device Tree 
