A PO file is made up of many entries, each entry holding the relation between an original untranslated string and its corresponding translation. All entries in a PO file usually pertain to a single project, and all translations are expressed in a single target language.
Lokalise parses the following keys:
# or #@ or #. (comment)
#, fuzzy (fuzzy flag)
Plural forms are accepted. Obsolete terms marked with (#~) are not imported from .po and .pot files.
As you upload the source .po files, Lokalise extracts the header and adds an archived key lokalise.po.header with the header content. To edit the contents, in the editor click Filter > QA > Archived. Copy/paste the contents of the header to all languages if required. You can also manually create this key, if necessary.