[standalone@localhost:9999 subsystem=logging] ./periodic-rotating-file-handler=FILE:read-resource-description
"append" =>

{ "type" => BOOLEAN, "description" => "Specify whether to append to the target file.", "access-type" => "read-only", "storage" => "configuration" }

,
and
[standalone@localhost:9999 subsystem=logging] ./periodic-rotating-file-handler=FILE:read-resource
{
"outcome" => "success",
"result" => {
"autoflush" => true,
"encoding" => undefined,
"formatter" => "%d

{HH:mm:ss,SSS}

%-5p [%c] (%t) %s%E%n",
"level" => "INFO",
"file" =>

{ "path" => "server.log", "relative-to" => "jboss.server.log.dir" }

,
"suffix" => ".yyyy-MM-dd"
},

Probably the same for other kinds of appenders.