Meta template that returns "yes" if evaluated during substitution, and the empty string if evaluated during transclusion.
Note that this template must be used in safesubst mode to work properly:

{{ safesubst:<noinclude/>issubst}}

• "{{issubst}}" → ""
• "{{subst:issubst}}" → "yes"

• {{require substitution}} – Prints an error unless substituted.
• {{substituted or transcluded}} – if-then-else metatemplate that checks if a template is currently being substituted or transcluded
  • {{always substitute}} – For the doc of the above templates; prints a message asking for it be substituted.
  • {{never substitute}} – The reverse of {{always substitute}}. For the doc of templates which should not be substituted; prints a message asking for it not to be substituted.
  • {{may be substituted}} – For the doc of templates whose substitution is optional.
  • {{substitution}} – Allows free-fill description of whether the template should be substituted and under what conditions.
• {{ifsubst}} – Forks if substituted or not.
• {{issubst}} – Returns "yes" if substituted.
• {{HTML comment}} – To sign substitutions with comments that contain wikitext expansions
• Module:Unsubst – Prevents substitution.
• Module:Unsubst-infobox – Prevents substitution for infoboxes, cleans up parameters.