multimedia.txt contain images and gbif_id
occurrence.txt contains location and gbif_id

What is the Darwin Core Archive download format? What's contained in the file? This format is a TDWG Standard and contains rich information. It is a ZIP file containing the original data as shared by the publisher, and the interpreted view after data has gone through quality control procedures. This is a richer format than simple CSV but provides the most complete view of data. Additional files provide supplementary information such as links to images (but not the actual image files). https://docs.gbif.org/course-data-use/en/files-for-download.html more on Darwin Core Archive here https://docs.gbif.org/course-data-use/exercise-data/Biodiversity_Data_Use_Processing.pptx.pdf

https://www.gbif.org/faq?question=what-is-inside-a-gbif-download-zip-file

What is inside a GBIF download zip file?

When you request a download in the GBIF data portal, you will receive a Darwin Core Archive file (DwC-A). This is the most widely-used data exchange file format in the GBIF network. To open it, you will need a zip programme installed in your computer (practically all modern operating systems include support for this kind of file). Just double-click on it to see its contents. Inside the zip file, you will find the following components:

An occurrence data file, 'occurrence.txt': A tab-separated data file that contains all the species occurrences included in your download. A citations file, 'citation.txt': A tab-separated data file that includes all the citation strings for the sources of the data you downloaded. A use rights file, 'rights.txt': A tab-separated data file that includes any additional use conditions or rights defined by the data publishers responsible for the data you downloaded. A metadata file, 'metadata.xml': This xml file stores all the information describing the contents of the downloaded dataset. A descriptor metadata file, 'meta.xml': This xml file describes the structure of the Darwin Core Archive so the whole archive can be processed automatically by software. To open the different files, please follow these instructions:

For tab-separated data files '.txt': These can be opened by any spreadsheet processor (e.g. MS Excel, OpenOffice Calc) or desktop database software (e.g. MS Access). Just open one of the suggested programmes and drag & drop the file into it, or import data by choosing 'tab delimited', CSV, 'text file' or any similar option. If you are asked to select an 'encoding standard' or 'character set' manually, please choose 'Unicode, UTF-8'. NOTE: do not try to double-click on the files, as .txt is a very generic extension and will probably have a generic text viewer associated to it. For xml files '.xml': These files are usually designed to be machine processed. If you are curious about their content, they can normally be interpreted by web browsers: just drag & drop the file into a web browser window. You will require special software if for any reason you want to edit these files manually.

More info: https://techdocs.gbif.org/en/data-use/download-formats

Reference:

GBIF.org (2024), GBIF Home Page. Available from: https://www.gbif.org [13 January 2020].