Tech pack, tech specs, production rider, tech manual. Regardless of what you call it the info you receive from a venue’s production manager or technical director is taken for granted when it's great, but aggravating when it's not.
The scope of a tech pack varies quite a bit. For small listening rooms, you may get a simple one sheet with some contact info, stage dimensions, and audio specs.
For club shows you begin to get much more insight, starting with contact info for the venue’s in house crew and parking details for your truck(s) and busses. You’ll also find technical details of the room including audio, lighting and any in house video they may offer. Backstage details such as the number of green rooms & showers, any touring production offices available, and catering options are often included as well.
You’ll often find load in specifics and any concerns related to this such as space or weight restrictions.

In addition to all the details mentioned above its fairly standard practice for theatres to also give you their line set schedule, which are specific measurements of every batten above the stage, the weight each batten is capable of holding and notification of any with a predetermined function (drapery, scenery, electrical).  They often alert you to any restrictions on the use of haze as well, which is fairly common in theatres.

Due to the large, accommodating nature of arenas, you'll typically receive general info on the space. Dimensions and the weight capacity of the rigging grid, available floor space, seating charts, and the number & size of the power disconnects available.

For many venues, you’ll also receive union specifics when there is a contract with a local labor union in place. Every contract is different and they vary quite a bit, some are easy to understand, others not so much.

Some venues go the extra mile to give you details regarding in house laundry when available, driving & arrival directions for your trucks and buses, even a list of local points of interest such as restaurants, coffee shops, gyms, and hospitals.

Just like a well-written tour rider, a thorough & detailed venue tech pack can save everyone involved a fair amount of time. You may have come across some tech packs that you were grateful for, and many that left you with unanswered questions. Naturally, the ones that save me time and make my day more efficient are the ones I appreciate receiving in my inbox.