{"id":"zlib-acknowledgement","title":"zlib/libpng License with Acknowledgement","reviewed_on":"2026-09-22","reviewer":"Giray Havur","text_source":"https://raw.githubusercontent.com/spdx/license-list-data/main/text/zlib-acknowledgement.txt","text_retrieved":true,"verdict":"created","summary":"Models the zlib text as the NUnit authors published it, with one word changed that changes the licence: the acknowledgment in the product documentation is required rather than appreciated. The record is TheZlibLibpngLicense plus a cc:Attribution and a dalicc:addStatement duty, and the prescribed acknowledgement wording is quoted.","findings":[{"rubric":1,"severity":"info","field":"spdx:licenseId","description":"File name, record identifier, SPDX identifier and IRI local name are all zlib-acknowledgement.","action":"applied"},{"rubric":2,"severity":"info","field":"odrl:target","description":"One odrl:AssetCollection of dct:type dcmitype:Software, following TheZlibLibpngLicense.","action":"applied"},{"rubric":3,"severity":"major","field":"odrl:permission","description":"The grant reads \"Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions\". The record permits reproduce, distribute, modify, derive, display, present, commercial use, derivative works, modified works and the distribution fee.","action":"applied"},{"rubric":3,"severity":"major","field":"odrl:permission","description":"dalicc:ChangeLicense is permitted with the dalicc:compliantLicense duty: the notice and the acknowledgement have to survive a relicensing, and nothing bars one.","action":"applied"},{"rubric":4,"severity":"minor","field":"odrl:prohibition","description":"No prohibitions. The text has no endorsement or trademark clause, as the zlib text has none.","action":"none"},{"rubric":5,"severity":"major","field":"odrl:duty","description":"cc:Attribution and dalicc:addStatement hang off odrl:distribute, odrl:modify and odrl:derive for restriction 1, \"If you use this software in a product, an acknowledgment (see the following) in the product documentation is required\". cc:Attribution carries the credit and dalicc:addStatement carries the prescribed wording that has to be attached; the wording itself is quoted in dalicc:additionalClauses.","action":"applied"},{"rubric":5,"severity":"minor","field":"odrl:duty","description":"cc:Notice hangs off the same three acts for restriction 3, \"This notice may not be removed or altered from any source distribution\", and dalicc:modificationNotice and dalicc:rename off odrl:modify and odrl:derive for restriction 2.","action":"applied"},{"rubric":6,"severity":"minor","field":"dalicc:WarrantyDisclaimer","description":"The opening paragraph carries the warranty sentence and the liability sentence and is split into the two predicates, as on TheZlibLibpngLicense, which keeps the same two sentences.","action":"applied"},{"rubric":7,"severity":"info","field":"cc:jurisdiction","description":"The text names no legal system and sets no term, so cc:jurisdiction is dalicc:worldwide and dalicc:validityType is dalicc:perpetual.","action":"applied"},{"rubric":8,"severity":"info","field":"dalicc:additionalClauses","description":"No clause of this text needs a term the vocabulary does not have. The prescribed acknowledgement is quoted as a literal of its own so that a reader sees the exact wording the duty asks for.","action":"none"},{"rubric":9,"severity":"info","field":"record","description":"The consistency check of app.services.composer against the dependency graph dg_default returned an empty conflict list.","action":"none"},{"rubric":10,"severity":"info","field":"record","description":"Read against licensedata/licenses/TheZlibLibpngLicense.ttl the record adds two duties, cc:Attribution and dalicc:addStatement, and nothing else. That is the whole difference between the two licences: the zlib text says an acknowledgment \"would be appreciated but is not required\" and this one says it is required.","action":"none"}],"family":"Permissive variants","port_of":null,"variant_kind":null,"variant_of":null,"notes":"cc:legalcode and dct:source both point at the SPDX page. The prescribed acknowledgement names the NUnit copyright holders, because the SPDX text is the one that project published."}