" Double quotation mark
' Single quotation mark
{} Curly brackets
[] Square brackets
- minus
_ Underscore
# Number sign
% Percent sign
& Ampersand
Euro sign
$ Dollar sign
£ Pound sign
² Exponents (0 - 9)

If you wish to use special characters within your survey that are not included in this list, you can include them manually after the conversion in your questionnaire.tex file.
https://survey.codes/click/chartable.html
survey.codes
crawl=CC-MAIN-2020-45
3431
application/http; msgtype=response
sha1:FZXQG33GKFNFVLP5QCEZEM7IT5DTASNN
<urn:uuid:3a9bad7d-f7f9-4793-9c24-69b835be122b>
2020-10-20T17:17:26Z
85.214.167.33
text/html
sha1:NWR2A7QBRSKXGOPZW4CDPE2D545VSW56
<urn:uuid:b6719b67-bf69-4b4d-8ce3-b2a31fa4e295>
https://survey.codes/click/chartable.html
response
<urn:uuid:6f2d24b4-5fdb-4e12-9fde-60ae8b00cda5>
isPartOf: CC-MAIN-2020-45
publisher: Common Crawl
description: Wide crawl of the web for October 2020
operator: Common Crawl Admin (info@commoncrawl.org)
hostname: ip-10-67-67-120.ec2.internal
software: Apache Nutch 1.17 (modified, https://github.com/commoncrawl/nutch/)
robots: checked via crawler-commons 1.2-SNAPSHOT (https://github.com/crawler-commons/crawler-commons)
format: WARC File Format 1.1
conformsTo: http://iipc.github.io/warc-specifications/specifications/warc-format/warc-1.1/