I want to find daily newspapers that are freely available online through the ZDB-Katalog. Based on the website's help section, explain how to search for these, specifying the exact filter options to use. Also, confirm whether the ZDB-Katalog contains individual newspaper articles.
Navigate to the 'Services' page from the homepage. Click on the 'Hilfe zur Suche' (Help for searching) link under 'Schnittstellen' (Interfaces). Locate the section detailing search indexes and identify the filter for newspaper frequency. Identify the filter for freely available online content. Determine from the help text whether individual newspaper articles are indexed. Synthesize the identified information to answer the query.
State that daily newspapers can be found by using the 'erf' (Erscheinungsfrequenz/frequency) index, specifying 'täglich' (daily) as the value. State that online freely available content can be found by using the 'kfr' (online kostenfrei verfügbar/online freely available) index with a value of '1'. Confirm that the ZDB-Katalog does NOT contain individual newspaper articles, but rather indexes publications at a higher level (e.g., 'Zeitung').