Fixed in git commit f9fe1ad758a7447a3c96f8c3ae9ce407095c8d20 which landed in the MediaWiki 1.29 version, but was not backported to 1.28. Try downloading the 1.29 version or fix the typo manually: replace escape() with escaped()
Also use the version for MW 1.29 for MW 1.28
Fixed in git commit f9fe1ad758a7447a3c96f8c3ae9ce407095c8d20 which landed in the MediaWiki 1.29 version, but was not backported to 1.28. Try downloading the 1.29 version or fix the typo manually: replace escape() with escaped()