This is the anatomy of the json url that is searching via keyword and refiner:
http://your-site/Search/Pages/Results.aspx#Default={"k":"custom refiner","r":[{"n":"FileType","t":["equals(\"docx\")","equals(\"doc\")","equals(\"docm\")","equals(\"dot\")","equals(\"nws\")","equals(\"dotx\")"],"o":"or","k":false,"m":null},{"n":"DisplayAuthor","t":["\"ǂǂ456c696f20537472757966\""],"o":"and","k":false,"m":null}]}
Where:
k: keyword; r: refinement filter; n: refiner name; t: refiner tokens;
o: operator (and, or); k: use KQL (Boolean); m: this is the token to
display value map. It's used when a custom refinement value (textbox)
is used. This stores the value that you inserted, to visualize it in
the refiner. Example: "m":{"equals(\"Item Value Text Box\")":"Item
Value Text Box"}
The url in the browser will be url encoded. You must use a tool like:
https://meyerweb.com/eric/tools/dencoder/
To decode your URL