The Afghan Partner Unit was a secretive Special Forces formation of the Afghan National Army that fought alongside US Special Forces as the Afghan version of JSOC (US Joint Special Operations Command). In 2013, it officially started using the “1st Ktah Kas” Battalion designation , abbreviated “KKA” (source: https://www.thedrive.com/the-war-zone/10114/this-shadowy-afghan-unit-fights-alongside-americas-most-elite-forces), though members have been photographed with insignia using “APU” terminology long after this change (source: https://nara.getarchive.net/media/a-ktah-khas-afghan-female-tactical-platoon-member-fa7e34, image from 2016) through July 2021 (source: https://www.youtube.com/watch?v=JR5xdLulcyc).
“Ktah Kas” is Dari Persian for “To Touch Success” (source: https://www.thedrive.com/the-war-zone/10114/this-shadowy-afghan-unit-fights-alongside-americas-most-elite-forces).
In 2012, the Afghan Partner Unit adopted the Hyperstealth Ghostex Kilo-1 camouflage pattern for their uniforms. The cloth was printed in the United States and sent to Afghanistan for final assembly into uniforms (source: https://hyperstealth.com/APU/index.html).
Helmet:
The helmet is a cut-down 2011 dated PASGT with the area around the ears removed to accommodate headphones, known as a “high cut” design. The Ghostex Kilo-1 camouflage material came from old APU uniforms and was glued onto the exterior of the helmet along with the velcro.
Tag:
2011 contract date and “PASGT” on the label.
Helmet Edges:
Excess material from PASGT design was cut away for a “high cut” to accommodate a headset. The edges were sealed by rubber though some composite can be seen through the cracks.
Liner System:
2008 dated buckle. 
Helmet suspension/liner appears to be hand-made from other helmets’ parts. The chinstrap appears to be from a US ACH helmet with a 2008 dated foliage green buckle. The helmet band was salvaged from some Level 3A body armor part manufactured by Anjani Technoblast Ltd. in India.
Writing:
Dari Persian text is written on a sticker and directly on the material.
Usage Photos:
Jan. 14, 2013: A member of the Afghan special forces, left, briefs soldiers after a training exercise on the outskirts of Kabul, Afghanistan. (Photo by Musadeq Sadeq, Associated Press; from https://www.deseret.com/2013/3/30/20450057/us-commandos-hand-over-troubled-area-to-afghans). 
May 11, 2013: Afghan coalition security force members search a home during an operation in Arghandab district, Kandahar province, Afghanistan. The operation resulted in the arrest of two extremists who were in charge of a group of fighters responsible for attacks against Afghan and coalition forces. (U.S. Army photo by Spc. Matthew Hulett, from https://www.dvidshub.net/image/966546/operation-arghandab-district). 
July 8, 2014: A member of the Afghan security forces returns fire on opposing enemy forces on an objective during a validation exercise training mission on Forward Operating Base Shank, Logar province, Afghanistan. The training was conducted to demonstrate their proficiency in carrying out missions independently of coalition forces. (U.S. Army photo by Spc. Steven Hitchcock, from https://www.dvidshub.net/image/1482861/validation-exercise-training-mission). 
September 29, 2015: Afghan special forces on the offensive to retake Kunduz from the Taliban (from https://twitter.com/afpfr/status/648766791490121728/photo/1). The patch has “Afghan Partnering Unit” on it (source: https://oefoif.forumotion.net/t4939-afghan-partnering-unit-apu). 
May 29, 2016: Ktah Khas Afghan Female (some sources say “Family”) Tactical Platoon (FTP) members perform a close quarters battle drill drill outside Kabul, Afghanistan. The females work closely alongside the males on operations to engage and interact with women and children. The FTPs are trained in marksmanship, language, fast roping and other combat-related skills. (U.S. Air Force photo by Staff Sgt. Douglas Ellis/Released, from https://nara.getarchive.net/media/ktah-khas-afghan-female-tactical-platoon-members-perform-77ba79). The FTP is based on the American Cultural Support Teams (CST on patch), which also employs female operatives in intelligence gathering roles. 
April 12, 2018: Female Tactical Platoon members fire during a qualification at range near Kabul, Afghanistan, Mar. 13, 2018. FTP training focuses on marksmanship, language and combat-related skills, preparing them to serve with Afghan Special Security Forces on operations requiring interaction with women and children (U.S. Air Force photo by Staff Sgt. Douglas Ellis, from )https://en.wikipedia.org/wiki/File:Female_Tactical_Platoon_Members.jpg).
From https://www.dvidshub.net/image/1050460/operation-helmand-province. 
From https://www.dvidshub.net/image/1050464/operation-helmand-province.
Similar helmets with Ghostex Kilo-1 fabric pasted to the outside were used until the fall of the Islamic Republic of Afghanistan in August 2021.
July 2021: Afghan special forces graduating (from https://news.sky.com/story/afghanistan-at-least-400-uk-trained-afghan-special-forces-troops-hiding-from-taliban-and-want-uk-evacuation-12402298). 
July 17, 2021: Masked Afghan Army Special Forces attend their graduation ceremony after a three-month training program at the Kabul Military Training Center, in Kabul, Afghanistan (AP Photo, from https://www.dailysabah.com/politics/diplomacy/nato-launches-military-training-for-afghan-special-forces-in-turkey).
Photos above appear to come from the event shown in this video: https://www.youtube.com/watch?v=JR5xdLulcyc
This appears to be a Ktah Khas graduation event as seen by the various KKA-marked items and APU patches. There are some members wearing Ghostex Kilo-1 uniforms as well.