We have a fair few tasks of the form "Linter X cannot be customized" (usually refer to the message severities). See, for example:

• D10498: It is not possible to change message severities for Cppcheck linter
• D12034: Let ArcanistPuppetLintLinter respect severity/severity.rules maps
• D11657#133770
• D10741#136127

The issue here is that ArcanistLinter has too much control over the ArcanistLintMessages that it produces (specifically, it sets the severity explicitly).