Make your mod work with Path of Valheiman

<Reference Include="PathOfValheiman">
  <HintPath>libs\PathOfValheiman.ref.dll</HintPath>
  <Private>false</Private>
</Reference>

[BepInPlugin("my.mod", "My Mod", "1.0.0")]
[BepInDependency("treextr.pathofvalheiman", BepInDependency.DependencyFlags.SoftDependency)]
public class MyMod : BaseUnityPlugin
{
    public static bool Pov => Chainloader.PluginInfos.ContainsKey("treextr.pathofvalheiman");
    void Update() { if (Pov) PovBridge.Tick(); }
}

// Only this class mentions PoV types: it is never loaded when PoV is absent.
static class PovBridge
{
    public static void Tick()
    {
        if (!Valheiman.Api.Pov.Has("progress")) return;
        int points = Valheiman.Api.Progression.FreePoints;
    }
}

Pov.Guid          // "treextr.pathofvalheiman"
Pov.Version       // "1.1.0" - the API's version, not the mod's
Pov.AtLeast(1, 0) // this API is 1.0 or newer within major 1
Pov.Has("storage")
Pov.Changed += areas => { /* "equipment", "keys", "purse", "looks", "progress", "host" */ };

Progression.Level; Progression.Xp; Progression.XpToNextLevel;
Progression.FreePoints; Progression.SpentPoints;
Progression.HasNode("node-id"); Progression.Nodes;      // taken node ids
Progression.TreeOpen;                                     // the tree window is open
Stats.Get("XpGainPct"); Stats.Has("TidyPack"); Stats.Names;   // unknown names read 0
Shield.Enabled; Shield.Current; Shield.Max; Shield.Regenerating;
Build.Path;              // dreng, skitalets, koldun, ratnik, trickster, warden - or null
Build.PathTitle;         // in the player's language
Build.AscendancyClass;   // or null
Build.Masteries;         // category -> chosen options

Events.CharacterLoaded += player => { };
Events.LevelUp        += level  => { };
Events.NodeTaken      += nodeId => { };
Events.NodeRemoved    += nodeId => { };
Events.StatsChanged   += ()     => { };   // read Stats again
Events.LootRolled     += items  => { };   // PoV rolled kill loot for the local player (rarity and affixes set)

Grant.TreeXp(120f, XpKind.Kills, "my.mod");   // counted like PoV's own XP of that kind
Grant.ProfessionXp("smith", 40);              // one craft-tree profession
Crafting.Professions;   // miner, smith, armorer, woodcutter, builder, shipwright, sailor, hunter, herder, cook,
                        // brewer, beekeeper, farmer, forager, fisher, pathfinder, delver
Crafting.TotalXp; Crafting.HasNode("craft-node-id");

// In Awake, on every machine:
SkillFreeze.Exempt(mySkillType);   // true; false for a Valheim skill (those stay PoV's)
SkillFreeze.Frozen;                // the freeze is on in this world
SkillFreeze.IsExempt(type);

Equipment.On;              // the system is on
Equipment.TurnedOffFor;    // the other equipment mod that keeps the slots instead, or null
foreach (CellInfo c in Equipment.Cells) { c.Id; c.Kind; c.Index; c.Title; c.Worn; }
Equipment.ItemIn(player, "food.0");
Equipment.IsOpen(player, "potion.2");    // food/potion/arrow cells depend on the belt and quiver worn
Equipment.Accepts("tool.3", item);
Equipment.Put(player, "food.1", item);   // worn cells: wears the item; false if refused
Equipment.TakeOut(player, "helmet");
Equipment.GridPosition(player, "key.0"); // where the cell's item lies; (-1,-1) if none
Equipment.IsCellPosition(player, pos);   // sorters and stackers: leave these positions alone
Equipment.BackpackRows(player);
Equipment.FoodCells(player); Equipment.PotionCells(player); Equipment.ArrowCells(player);
Equipment.KeyLabel("tool.0");            // "Alt+1"
Purse.Open(player); Purse.Coins(player); Purse.Empty(player);
Trinkets.Seats; Trinkets.OrdinarySeats; Trinkets.Worn(player);

class MyStorage : IStorageProvider
{
    public string Id => "my.guid";
    public int Contract => Storage.Contract;                                // 1
    public ItemDrop.ItemData ItemIn(Player p, string cell) { ... }          // never moves anything
    public bool Put(Player p, string cell, ItemDrop.ItemData item) { ... }  // move it, or change nothing
    public bool TakeOut(Player p, string cell) { ... }                      // into the backpack; false if no room
}

string refused = Storage.Register(new MyStorage());   // in Awake, before a character loads; null = accepted
Storage.Changed("food.0");                            // once after every committed change

Looks.CanChange(item); Looks.Choices(item); Looks.IsOpen(look); Looks.Current(player, item);
Looks.SameLook(a, b); Looks.HiddenLook;
Looks.WhyNot(player, item, look, canHide);    // null when allowed, else a translated reason
string refused = Looks.Apply(player, list);   // (item, look, canHide) tuples; one Rune of Guise each
Looks.Reset(player, item); Looks.Runes(player); Looks.RuneIcon;
using var portrait = Looks.CreatePortrait(rawImage);   // Tick(player) each frame, Turn(deg), ShowBackground, TryOn

Rarity r = Items.RarityOf(item);   // Common, Magic, Rare, Unique, Legendary
Items.RarityTitle(r); Items.RarityNameColor(r); Items.RarityFrameColor(r);
Items.Signature(item);             // changes when anything PoV keeps on the item changes: redraw then
string type = Tooltip.Describe(item, out var rows);   // AffixRow: Name, Effect, Tint, Socket, EmptySocket, Warning
Items.HostRarityFrames("my.guid"); // you draw rarity frames on inventory cells; PoV stops

Items.IsCorrupted(item); Items.IsIdentified(item); Items.ItemLevel(item); Items.IsJewel(item);
foreach (AffixInfo a in Items.Affixes(item))       // empty while the item is unidentified
{
    a.Id;            // stable affix id from the loot catalogue, or the unique line's mechanic id
    a.Place;         // Prefix, Suffix or Unique (unique items and jewels)
    a.Tier;          // "T1", "T2" ... or ""
    a.Value;         // the rolled number, as the tooltip shows it
    a.Min; a.Max;    // the tier's roll range, already scaled for the item's slot
    a.Text;          // the tooltip line in the player's language
    a.Local;         // works on the item itself (weapon damage, armour) instead of the character
    foreach (AffixStat st in a.Stats) { st.Stat; st.Form; st.Value; st.Subjects; }   // PoV stat names, see Stats.Names
}
foreach (ImplicitInfo i in Items.Implicits(item)) { i.Id; i.Value; i.Min; i.Max; i.Text; }   // e.g. belt food/potion slots
foreach (SocketInfo s in Items.Sockets(item)) { s.Kind; s.Sigil; }   // "runic" / "corrupted" / "divine", sigil prefab or null
Items.Influences(item);                              // influence ids

Rows.Extra;                 // extra backpack rows the tree gives
Rows.Host("my.guid");       // you size the inventory; PoV stops changing its height
Conveniences.CraftFromChests; Conveniences.ChestReach(station); Conveniences.ChestCircleShown = true;
QuickStack.Available; QuickStack.StackKey; QuickStack.SortKey;
QuickStack.HostButtons("my.guid");   // you show the buttons; PoV's hotkeys keep working

foreach (HudPiece p in HudPieces.Pieces()) { p.Id; p.Title; p.Rect; p.ClaimedBy; }
HudPieces.Claim("level", "my.guid");   // PoV stops moving and fading it; null gives it back

Creatures.RarityOf(c);      // Magic, Rare, Unique from stars; Common when PoV's creature rarity is off
Creatures.Stars(c);
Creatures.ModifiersOf(c);   // ids: swift, furious, armored, warded, burning, ...
Creatures.Modifiers;        // every modifier: Id, Title, About
Creatures.Level(c); Creatures.BiomeLevel(Heightmap.Biome.Swamp);
Creatures.IsPovBoss(c);     // PoV's own monolith bosses
Creatures.DamageFactor(c);  // how much PoV multiplies its damage

// In Awake, on every machine (server and clients):
Creatures.LeaveAlone("Bonemass", "my.guid");

Difficulty.Preset;          // 0 vanilla creatures, 1 easy, 2 normal, 3 hard, 4 merciless
Difficulty.PresetTitle;
Difficulty.VanillaCombat;   // Valheim's Combat modifier: 0 very easy ... 4 very hard, 5 none of these
Difficulty.MonsterPower(c); // altar monster power for this creature (1 = none)