why there are a lot of s__uncultured_bacterium_qiime_unique_taxon_tag_xxxx and norank_qiime_unique_taxon_tage was found in the taxonomy classification result

[LuffyLuffy]

Hi, rdpstaff group,
When I use
java -Xmx1g -jar /path/to/classifier.jar classify -t mytrained/rRNAClassifier.properties -o result.tax.txt asv_seqs.fasta
and found that there there is a lot of s__uncultured_bacterium_qiime_unique_taxon_tag_xxxx and o__norank_qiime_unique_taxon_tag_xxxx results in my taxonomic classification result.

But I have seen any unique taxon_tag in my raw database.
Is this norank or uncultured came from classifier.jar ?