Doesn't happen with the English Wikipedia version.
Error: Something went wrong. Could not fill variables in: (undefined) undefined
at fillVariables (/app/node_modules/infobox-parser/build/bundle.min.js:1:1957)
at fillVariablesUntilDone (/app/node_modules/infobox-parser/build/bundle.min.js:1:2659)
at fillVariablesUntilDone (/app/node_modules/infobox-parser/build/bundle.min.js:1:2695)
at getVariableValue (/app/node_modules/infobox-parser/build/bundle.min.js:1:3339)
at reduceVariable (/app/node_modules/infobox-parser/build/bundle.min.js:1:3755)
at /app/node_modules/infobox-parser/build/bundle.min.js:1:3935
at Array.reduce (native)
at extractProperties (/app/node_modules/infobox-parser/build/bundle.min.js:1:4114)
at index (/app/node_modules/infobox-parser/build/bundle.min.js:1:9971)
at /app/node_modules/wikijs/dist/page.js:1:1579
at process._tickDomainCallback (internal/process/next_tick.js:135:7)
That happens when I search for "Wayne Rooney" using https://de.wikipedia.org/w/api.php
Doesn't happen with the English Wikipedia version.