ConfigDB:
Table 'solrCoreStores' will contain URIs to existing core stores. These are mount points within the file systems where the physical indices will be stored.
CREATE TABLE (
uid=1000(service) gid=1000(service) Gruppen=1000(service) int(10) unsigned NOT NULL,
varchar(255) COLLATE utf8_unicode_ci NOT NULL,
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
PRIMARY KEY (uid=1000(service) gid=1000(service) Gruppen=1000(service))
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Per Schema:
Table 'solrCores' keeps track of existing cores and where they are stored (i.e. in which core store).
CREATE TABLE (
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
tinyint(1) unsigned NOT NULL,
varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
PRIMARY KEY (,,),
KEY (,),
KEY (),
KEY ()
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Table 'indexedFolders' keeps track of the indexing-state of folders. Mainly it tracks wich folders have already been indexed initially.
CREATE TABLE (
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
int(10) unsigned NOT NULL,
varchar(128) COLLATE utf8_unicode_ci NOT NULL,
varchar(128) COLLATE utf8_unicode_ci NOT NULL,
bigint(64) NOT NULL,
tinyint(1) unsigned NOT NULL,
tinyint(1) unsigned NOT NULL,
PRIMARY KEY (,,,,),
KEY (,,),
KEY (,,,)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci