--- license: unknown language: - is pretty_name: IC3-v2 size_categories: - 1B The Icelandic Clean Crawled Corpus v2 (IC3-v2) is a collection of quality-filtered plaintext documents in Icelandic extracted from scraped websites with the `.is` top-level domain (TLD) in Common Crawl dumps between the years 2013 and 2023. The corpus contains about 1.3 billion words across almost 4 million documents. ## Dataset Details We extract all WARC records matching the `.is` TLD from all available Common Crawl dumps as of the end of year 2023. Using a manually curated blacklist of domain names, we remove records from websites with gambling, pornography, and other illegal or harmful content. We extract the plaintext from the corresponding raw HTML code using `trafilatura` (with `jusText` as fallback). During the extraction process, `trafilatura` uses heuristics to provide fields such as `title`, `author` and `tags`, which we include as document-level metadata. We then apply various hand-crafted quality filters, similar to the Gopher rules and FineWeb filters, on the extracted output in an attempt at excluding low-quality documents like SEO product pages, documents with a high number of repeated sentences, etc. On the high-quality documents, we then run FAIR's `fasttext` language identification model and only keep documents with high proportion of Icelandic text. Finally, we run deduplication on the corpus. This we do by both running a sliding window of three sentences across each document and removing the span if it was previously seen in any document before, and also by performing document-wise exact string-matching deduplication across the corpus. Please note that even though the documents have been URL-filtered for harmful content on a best-effort basis, some may still remain.