You can’t add search engines with the browser GUI, perhaps because Ubuntu Touch is a Work-In-Progress and it’s still early days. Adding search engines to browsers still has patchy support from major browsers, even though the OpenSearch standard is donkey’s years old. I installed Ubuntu Touch on my Nexus 4 after experiencing the “Sleep Of Death” too many times and wanted to use my Firtl search proxy in Touch’s browser.
I located the configuration files (they’re OpenSearch XML description documents, which is handy!) by using grep -r to search for one of the existing search engine names. The search engine description documents are located (on my phone) in
The / filesystem appears to be mounted read-only and must be remounted read-write to make changes. I did this with the command
mount -o remount,rw /
Copy your search engine’s OpenSearch description document into this directory and next time you attempt to set Ubuntu Touch’s web browser’s search engine, you should see the new search engine in the list. Don’t forget to remount / read-only.