Plugin types are identified by unique IDs. At the time of writing plugin writers may request these from firstname.lastname@example.org. This may change, in which case http://www.ladspa.org is likely to provide information on new sources.
Plugin IDs 1-1000 are reserved for development use and plugins must not be released publicly with these IDs as clashes are likely. Plugin ID 0 will never be allocated.
It is hoped that plugin IDs will fit into 24bits. In the unlikely event that this range needs to be extended it will be, possibly with the addition of a second dimension (e.g. developer ID). In the meantime hosts may assume that IDs will not exceed 0x00FFFFFF.