Chatted to Olga today about targetting KaiOS users and suggesting to them that they try the app.
I suggested that it might be possible to use QuickSurveys to run an external survey where the link is
the app download.
We should first verify that KaiOS can run quicksurveys using https://en.m.wikipedia.beta.wmflabs.org/wiki/Spain?quicksurvey=true
If it does, we could run an external survey where the link is to the KaiOS app download, however we'd need to update QuickSurveys to allow targeting to certain user agents, likely by providing a configurable regular expression.
I think such a feature could have other applications so the feature would be useful beyond this particular use case.
# Acceptance criteria
 The SurveyAudience class will need to be extended to include a user agent field. I suggest this is a regular expression. This will add it to the page, readable by JS.
 The isInAudience method in ext.quicksurveys.libs/libs.js should check the field and match against user agent.
 Add a test to tests/qunit/ext.quicksurveys.lib