enable/control fts-tika debug logging in Dovecot 2.3.18 + Tika Server 2.4.0?

i run

dovecot-2.3.18-1.fc36.x86_64

i've installed Apache Tika, v 2.4.0

ls -al tika-server-standard-2.4.0.jar
	-rw-r--r-- 1 root root 59M May  2 09:53 tika-server-standard-2.4.0.jar

tika's listening

telnet 127.0.0.1 9998
  Trying 127.0.0.1...
  Connected to 127.0.0.1.
  Escape character is '^]'.
  telnet>

and responds to a test

curl \
-T /tmp/test.pdf \
http://127.0.0.1:9998/meta

  pdf:unmappedUnicodeCharsPerPage,0,0,0,0,0,0,0,0,0,0,0,0,0,0
  pdf:PDFVersion,1.4
  xmp:CreatorTool,Adobe InDesign 15.1 (Macintosh)
  pdf:hasXFA,false
  access_permission:modify_annotations,true
  access_permission:can_print_degraded,true
  X-TIKA:Parsed-By-Full-Set,org.apache.tika.parser.DefaultParser,org.apache.tika.parser.pdf.PDFParser
  dcterms:created,2020-08-13T14:55:46Z
  language,en
  dcterms:modified,2020-09-24T23:38:28Z
  dc:format,application/pdf; version=1.4
  xmpMM:DocumentID,xmp.id:8a612346-9d03-4caf-8ebf-da6f3716ed0a
  pdf:docinfo:creator_tool,Adobe InDesign 15.1 (Macintosh)
  access_permission:fill_in_form,true
  pdf:docinfo:modified,2020-09-24T23:38:28Z
  pdf:hasCollection,false
  pdf:encrypted,false
  pdf:hasMarkedContent,true
  Content-Type,application/pdf
  dc:language,en-US
  pdf:producer,Adobe PDF Library 15.0
  access_permission:extract_for_accessibility,true
  access_permission:assemble_document,true
  xmpTPg:NPages,14
  pdf:hasXMP,true
  pdf:charsPerPage,84,676,1653,1914,814,1022,645,1221,1087,732,887,1295,1263,149
  access_permission:extract_content,true
  xmpMM:DerivedFrom:DocumentID,xmp.did:b98726d4-04c4-48f5-88be-0a48a0074356
  access_permission:can_print,true
  pdf:docinfo:trapped,false
  X-TIKA:Parsed-By,org.apache.tika.parser.DefaultParser,org.apache.tika.parser.pdf.PDFParser
  xmpMM:DerivedFrom:InstanceID,xmp.iid:3dd6a91f-a114-4d63-804e-e2b749c15075
  pdf:annotationTypes,null
  access_permission:can_modify,true
  pdf:docinfo:producer,Adobe PDF Library 15.0
  pdf:docinfo:created,2020-08-13T14:55:46Z
  pdf:annotationSubtypes,Link

in dovecot config, i've added

plugin {
	fts_tika = http://127.0.0.1:9998/tika/
}

and

log_debug = (category=fts-flatcurve OR category=fts-tika)

on message receipt, I see verbose logs for fts-flatcurve, as expected, but not a trace of output from fts-tika, in dovecot logs

how to correctly turn on debug/verbose logging for fts-tika use in/by dovecot?